diff --git a/README.md b/README.md
index 9e5a699..a57d723 100644
--- a/README.md
+++ b/README.md
@@ -235,7 +235,7 @@ This places the generated code in `gen/python`. See the `Makefile` for more exte
 
 | Field | Type | Label | Description |
 | ----- | ---- | ----- | ----------- |
-| horizon_mins | [uint32](#uint32) |  |  || p50_fraction | [float](#float) |  |  || other_statistics_fractions | [CreateForecastRequest.ForecastValue.OtherStatisticsFractionsEntry](#ocf-dp-CreateForecastRequest-ForecastValue-OtherStatisticsFractionsEntry) | repeated | Struct for storing additional statistics like p10, p90, mean etc. || metadata | [google.protobuf.Struct](#google-protobuf-Struct) | optional |  |
+| horizon_mins | [uint32](#uint32) |  |  || p50_fraction | [float](#float) |  |  || other_statistics_fractions | [CreateForecastRequest.ForecastValue.OtherStatisticsFractionsEntry](#ocf-dp-CreateForecastRequest-ForecastValue-OtherStatisticsFractionsEntry) | repeated | Struct for storing additional statistics like p10, p90, mean etc. |
 </details><a name="ocf-dp-CreateForecastRequest-ForecastValue-OtherStatisticsFractionsEntry"></a>
 <details><summary>CreateForecastRequest.ForecastValue.OtherStatisticsFractionsEntry</summary>
 
diff --git a/internal/server/postgres/bench_test.go b/internal/server/postgres/bench_test.go
index 1ff73f2..6e2bbaa 100644
--- a/internal/server/postgres/bench_test.go
+++ b/internal/server/postgres/bench_test.go
@@ -12,7 +12,6 @@ import (
 	"github.com/jackc/pgx/v5/pgtype"
 	"github.com/rs/zerolog"
 	"github.com/stretchr/testify/require"
-	"google.golang.org/protobuf/types/known/structpb"
 	timestamppb "google.golang.org/protobuf/types/known/timestamppb"
 
 	pb "github.com/openclimatefix/data-platform/internal/gen/ocf/dp"
@@ -116,12 +115,6 @@ var yields = func() []*pb.CreateForecastRequest_ForecastValue {
 				"p90": 0.3,
 			},
 			HorizonMins: uint32(i * 30),
-			Metadata: func() *structpb.Struct {
-				s, _ := structpb.NewStruct(map[string]any{
-					"example_key": fmt.Sprintf("example_value_%d", i),
-				})
-				return s
-			}(),
 		})
 	}
 
diff --git a/internal/server/postgres/dataserverimpl.go b/internal/server/postgres/dataserverimpl.go
index e8544fb..4664d50 100644
--- a/internal/server/postgres/dataserverimpl.go
+++ b/internal/server/postgres/dataserverimpl.go
@@ -10,7 +10,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"math"
 	"time"
 
 	"github.com/google/uuid"
@@ -21,7 +20,6 @@ import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
-	"google.golang.org/protobuf/types/known/structpb"
 	"google.golang.org/protobuf/types/known/timestamppb"
 
 	pb "github.com/openclimatefix/data-platform/internal/gen/ocf/dp"
@@ -64,6 +62,19 @@ func timeptrToPgTimestamp(t *timestamppb.Timestamp) pgtype.Timestamp {
 	return pgtype.Timestamp{Time: t.AsTime().UTC(), Valid: true}
 }
 
+// extractSIPStatPtrFromMap gets a key's value from a map as a pointer, and converts it
+// to a smallint percentage. If it doesn't exist, it returns nil.
+func extractSIPStatPtrFromMap(m map[string]float32, key string) *int16 {
+	val, exists := m[key]
+	if !exists {
+		return nil
+	}
+
+	sip_val := int16(val * 30000.0)
+
+	return &sip_val
+}
+
 // --- Server Implementation ----------------------------------------------------------------------
 
 func NewDataPlatformDataServiceServerImpl() *DataPlatformDataServiceServerImpl {
@@ -172,48 +183,12 @@ func (s *DataPlatformDataServiceServerImpl) CreateForecast(
 	// Create the forecast data
 	paramsList := make([]db.CreatePredictedValuesParams, len(req.Values))
 	for i, value := range req.Values {
-		// Since the database wants each numeric value to have 4 significant figures,
-		// the float32 values need to be rounded accordingly.
-		roundedStats := make(map[string]any)
-		for k, val32 := range value.OtherStatisticsFractions {
-			val64 := float64(val32)
-
-			var roundedVal float64
-			if val64 < 1 {
-				roundedVal = math.Round(val64*10000) / 10000
-			} else {
-				roundedVal = math.Round(val64*1000) / 1000
-			}
-
-			roundedStats[k] = roundedVal
-		}
-
-		// Since CreatePredictedValues uses COPYFROM, manually coerce empty metadata to nil
-		if value.Metadata != nil && len(value.Metadata.Fields) == 0 {
-			value.Metadata = nil
-		}
-
-		var otherStats *structpb.Struct
-
-		if len(roundedStats) > 0 {
-			otherStats, err = structpb.NewStruct(roundedStats)
-			if err != nil {
-				l.Err(err).Msgf("structpb.NewStruct(%+v)", roundedStats)
-			}
-		}
-
 		paramsList[i] = db.CreatePredictedValuesParams{
 			HorizonMins:  int16(value.HorizonMins),
+			P10Sip:       extractSIPStatPtrFromMap(value.OtherStatisticsFractions, "p10"),
 			P50Sip:       int16(value.P50Fraction * 30000.0),
+			P90Sip:       extractSIPStatPtrFromMap(value.OtherStatisticsFractions, "p90"),
 			ForecastUuid: dbForecast.ForecastUuid,
-			TargetTimeUtc: pgtype.Timestamp{
-				Time: req.InitTimeUtc.AsTime().Add(
-					time.Duration(value.HorizonMins) * time.Minute,
-				),
-				Valid: true,
-			},
-			OtherStatsFractions: otherStats,
-			Metadata:            value.Metadata,
 		}
 	}
 
@@ -548,11 +523,13 @@ func (s *DataPlatformDataServiceServerImpl) StreamForecastData(
 						&row.ForecasterVersion,
 						&row.CreatedAtUtc,
 						&row.HorizonMins,
+						&row.P10Sip,
 						&row.P50Sip,
-						&row.OtherStatsFractions,
+						&row.P90Sip,
 						&row.CapacityWatts,
-						&row.InitTimeUtc,
 						&row.Metadata,
+						&row.InitTimeUtc,
+						&row.TargetTimeUtc,
 					)
 					if err != nil {
 						l.Err(err).Msg("rows.Scan failed")
@@ -560,10 +537,12 @@ func (s *DataPlatformDataServiceServerImpl) StreamForecastData(
 					}
 
 					otherStatistics := make(map[string]float32)
-					if row.OtherStatsFractions != nil {
-						for k, v := range row.OtherStatsFractions.AsMap() {
-							otherStatistics[k] = float32(v.(float64))
-						}
+					if row.P10Sip != nil {
+						otherStatistics["p10"] = float32(*row.P10Sip) / 30000.0
+					}
+
+					if row.P90Sip != nil {
+						otherStatistics["p90"] = float32(*row.P90Sip) / 30000.0
 					}
 
 					metadata := make(map[string]string)
@@ -1639,14 +1618,12 @@ func (s *DataPlatformDataServiceServerImpl) GetForecastAsTimeseries(
 		out := make([]*pb.GetForecastAsTimeseriesResponse_Value, len(dbPreds))
 		for i, pred := range dbPreds {
 			otherStats := make(map[string]float32)
-			for k, v := range pred.OtherStatsFractions.AsMap() {
-				floatVal, ok := v.(float64)
-				if !ok {
-					l.Warn().Str("key", k).Interface("value", v).Msg("skipping non-float statistic")
-					continue
-				}
+			if pred.P10Sip != nil {
+				otherStats["p10"] = float32(*pred.P10Sip) / 30000.0
+			}
 
-				otherStats[k] = float32(floatVal)
+			if pred.P90Sip != nil {
+				otherStats["p90"] = float32(*pred.P90Sip) / 30000.0
 			}
 
 			out[i] = &pb.GetForecastAsTimeseriesResponse_Value{
@@ -1741,14 +1718,12 @@ func (s *DataPlatformDataServiceServerImpl) GetForecastAsTimeseries(
 	values := make([]*pb.GetForecastAsTimeseriesResponse_Value, len(dbValues))
 	for i, value := range dbValues {
 		otherStats := make(map[string]float32)
-		for k, v := range value.OtherStatsFractions.AsMap() {
-			floatVal, ok := v.(float64)
-			if !ok {
-				l.Warn().Str("key", k).Interface("value", v).Msg("skipping non-float statistic")
-				continue
-			}
+		if value.P10Sip != nil {
+			otherStats["p10"] = float32(*value.P10Sip) / 30000.0
+		}
 
-			otherStats[k] = float32(floatVal)
+		if value.P90Sip != nil {
+			otherStats["p90"] = float32(*value.P90Sip) / 30000.0
 		}
 
 		values[i] = &pb.GetForecastAsTimeseriesResponse_Value{
diff --git a/internal/server/postgres/dataserverimpl_test.go b/internal/server/postgres/dataserverimpl_test.go
index 98ac857..3b5108c 100644
--- a/internal/server/postgres/dataserverimpl_test.go
+++ b/internal/server/postgres/dataserverimpl_test.go
@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"maps"
 	"math/rand/v2"
 	"strings"
 	"testing"
@@ -589,7 +588,6 @@ func TestGetForecastAtTimestamp(t *testing.T) {
 				"p90": float32(0.6 + float32(i)*0.05),
 				"p10": float32(0.4 + float32(i)*0.05),
 			},
-			Metadata: metadata,
 		}
 	}
 
@@ -1061,7 +1059,6 @@ func TestGetForecastAsTimeseries(t *testing.T) {
 				"p10": float32(max(float32(i-1)*float32(100/len(yields))/100.0, 0)),
 				"p90": float32(min(float32(i+1)*float32(100/len(yields))/100.0, 1.1)),
 			},
-			Metadata: metadata,
 		}
 	}
 
@@ -1801,8 +1798,6 @@ func TestCreateObservations(t *testing.T) {
 
 func TestGetWeekAverageDeltas(t *testing.T) {
 	pivotTime := time.Date(2025, 1, 1, 12, 0, 0, 0, time.UTC)
-	metadata, err := structpb.NewStruct(map[string]any{"source": "test"})
-	require.NoError(t, err)
 
 	// Create a site to attach the observations to
 	siteResp, err := dc.CreateLocation(t.Context(), &pb.CreateLocationRequest{
@@ -1862,7 +1857,6 @@ func TestGetWeekAverageDeltas(t *testing.T) {
 				"p10": float32(max(float32(i-1)*float32(100/len(yields))/100.0, 0)),
 				"p90": float32(min(float32(i+1)*float32(100/len(yields))/100.0, 1.1)),
 			},
-			Metadata: metadata,
 		}
 	}
 
@@ -1925,7 +1919,6 @@ func TestCreateForecast(t *testing.T) {
 				"p10": 0.4 + float32(i)*0.05,
 				"p90": 0.6 + float32(i)*0.05,
 			},
-			Metadata: metadata,
 		}
 	}
 
@@ -1935,7 +1928,6 @@ func TestCreateForecast(t *testing.T) {
 			HorizonMins:              uint32(i * 30),
 			P50Fraction:              0.0,
 			OtherStatisticsFractions: map[string]float32{},
-			Metadata:                 &structpb.Struct{},
 		}
 	}
 
@@ -1948,7 +1940,6 @@ func TestCreateForecast(t *testing.T) {
 				"p10": 1.3,
 				"p90": -0.2,
 			},
-			Metadata: metadata,
 		}
 	}
 
@@ -2078,11 +2069,8 @@ func TestCreateForecast(t *testing.T) {
 				})
 				require.NoError(t, err)
 
-				expectedMetadata := tc.req.Values[0].Metadata.AsMap()
-				maps.Copy(expectedMetadata, tc.req.Metadata.AsMap())
-
 				for _, val := range fResp.Values {
-					require.Equal(t, expectedMetadata, val.Metadata.AsMap())
+					require.Equal(t, tc.req.Metadata.AsMap(), val.Metadata.AsMap())
 				}
 			}
 		})
@@ -2130,7 +2118,6 @@ func TestGetLatestForecasts(t *testing.T) {
 				"p10": 0.4 + float32(i)*0.05,
 				"p90": 0.6 + float32(i)*0.05,
 			},
-			Metadata: metadata,
 		}
 	}
 
@@ -2247,7 +2234,6 @@ func TestStreamForecastData(t *testing.T) {
 			OtherStatisticsFractions: map[string]float32{
 				"p90": float32(i)*0.25 + 0.1,
 			},
-			Metadata: metadata,
 		}
 	}
 
@@ -2261,6 +2247,7 @@ func TestStreamForecastData(t *testing.T) {
 			EnergySource: pb.EnergySource_ENERGY_SOURCE_SOLAR,
 			InitTimeUtc:  initTime,
 			Values:       yields,
+			Metadata:     metadata,
 		})
 		require.NoError(t, err)
 
@@ -2270,6 +2257,7 @@ func TestStreamForecastData(t *testing.T) {
 			EnergySource: pb.EnergySource_ENERGY_SOURCE_SOLAR,
 			InitTimeUtc:  initTime,
 			Values:       yields,
+			Metadata:     metadata,
 		})
 		require.NoError(t, err)
 	}
diff --git a/internal/server/postgres/sql/migrations/00009_optimize_storage.sql b/internal/server/postgres/sql/migrations/00009_optimize_storage.sql
new file mode 100644
index 0000000..ffab5ad
--- /dev/null
+++ b/internal/server/postgres/sql/migrations/00009_optimize_storage.sql
@@ -0,0 +1,169 @@
+-- +goose NO TRANSACTION
+-- +goose Up
+
+/*
+ * Reduces the database size by approximately 40%.
+ *
+ * Modifies the predicted_generation_values table to optimize it's use of storage.
+ * This is done through changing the index, removing redundant columns, and replacing
+ * dynamic columns with small static ones.
+ *
+ * The schema modifications and the corresponding data changes are seperated out for
+ * faster migration. Since the predicted_generation_values table is very large, simple
+ * DELETES and UPDATES would take a long time, and not actually gain us any storage
+ * savings (at least until an autovacuum process ran). By instead moving the data
+ * partition-wise and then replacing the partitions, we keep the process light on CPU.
+ */ 
+
+DROP INDEX IF EXISTS loc.idx_sources_mv_gist_sys_period;
+
+CREATE INDEX IF NOT EXISTS idx_sources_mv_composite_lookup 
+ON loc.sources_mv USING gist (geometry_uuid, source_type_id, sys_period);
+
+ALTER TABLE pred.predicted_generation_values 
+    ADD COLUMN p10_sip SMALLINT, 
+    ADD COLUMN p90_sip SMALLINT,
+    DROP CONSTRAINT predicted_generation_values_pkey CASCADE,
+    ALTER COLUMN target_time_utc DROP NOT NULL;
+
+-- +goose StatementBegin
+CREATE OR REPLACE PROCEDURE pred.swap_predicted_generation_partitions()
+LANGUAGE plpgsql
+AS $$
+DECLARE
+    partition_record RECORD;
+    new_part_name TEXT;
+    part_bound TEXT;
+BEGIN
+    FOR partition_record IN
+        SELECT child.relname AS table_name,
+               pg_get_expr(child.relpartbound, child.oid) AS bounds
+        FROM pg_inherits
+        JOIN pg_class parent ON pg_inherits.inhparent = parent.oid
+        JOIN pg_class child ON pg_inherits.inhrelid = child.oid
+        JOIN pg_namespace nmsp_parent ON nmsp_parent.oid = parent.relnamespace
+        WHERE parent.relname = 'predicted_generation_values'
+          AND nmsp_parent.nspname = 'pred'
+    LOOP
+        new_part_name := partition_record.table_name || '_v2';
+        part_bound := partition_record.bounds;
+
+        EXECUTE format('CREATE TABLE pred.%I (LIKE pred.predicted_generation_values INCLUDING ALL);', new_part_name);
+
+        EXECUTE format('
+            INSERT INTO pred.%I (horizon_mins, p50_sip, p10_sip, p90_sip, forecast_uuid, target_time_utc, metadata, other_stats_fractions)
+            SELECT 
+                horizon_mins, 
+                p50_sip, 
+                ((other_stats_fractions->>''p10'')::REAL * 30000)::SMALLINT, 
+                ((other_stats_fractions->>''p90'')::REAL * 30000)::SMALLINT, 
+                forecast_uuid, 
+                NULL, 
+                NULL, 
+                NULL 
+            FROM pred.%I;
+        ', new_part_name, partition_record.table_name);
+
+        EXECUTE format('ALTER TABLE pred.%I ADD PRIMARY KEY (forecast_uuid, horizon_mins);', new_part_name);
+        EXECUTE format('ALTER TABLE pred.predicted_generation_values DETACH PARTITION pred.%I;', partition_record.table_name);
+        EXECUTE format('ALTER TABLE pred.predicted_generation_values ATTACH PARTITION pred.%I %s;', new_part_name, part_bound);
+        EXECUTE format('DROP TABLE pred.%I;', partition_record.table_name);
+        EXECUTE format('ALTER TABLE pred.%I RENAME TO %I;', new_part_name, partition_record.table_name);
+
+        COMMIT; 
+    END LOOP;
+END;
+$$;
+-- +goose StatementEnd
+
+CALL pred.swap_predicted_generation_partitions();
+DROP PROCEDURE pred.swap_predicted_generation_partitions;
+
+ALTER TABLE pred.predicted_generation_values
+    DROP COLUMN target_time_utc,
+    DROP COLUMN other_stats_fractions,
+    DROP COLUMN metadata,
+    ADD PRIMARY KEY (forecast_uuid, horizon_mins);
+
+DROP TABLE IF EXISTS pred.predicted_generation_values_template;
+CREATE TABLE pred.predicted_generation_values_template (
+    horizon_mins SMALLINT NOT NULL,
+    CONSTRAINT horizon_mins_nonnegative_check CHECK (horizon_mins >= 0),
+    CONSTRAINT horizon_mins_fiveminutely_check CHECK (horizon_mins % 5 = 0),
+    p50_sip SMALLINT NOT NULL,
+    CONSTRAINT p50_sip_nonnegative_check CHECK (p50_sip >= 0),
+    p10_sip SMALLINT,
+    p90_sip SMALLINT,
+    forecast_uuid UUID NOT NULL REFERENCES pred.forecasts (forecast_uuid) ON DELETE CASCADE ON UPDATE CASCADE, 
+    PRIMARY KEY (forecast_uuid, horizon_mins)
+);
+
+ANALYZE pred.predicted_generation_values;
+
+
+-- +goose Down
+ALTER TABLE pred.predicted_generation_values
+    DROP CONSTRAINT predicted_generation_values_pkey CASCADE,
+    ADD COLUMN target_time_utc TIMESTAMP,
+    ADD COLUMN other_stats_fractions JSONB DEFAULT NULL,
+    ADD CONSTRAINT other_stats_nullifempty CHECK (other_stats_fractions IS NULL OR other_stats_fractions != '{}'),
+    ADD CONSTRAINT other_stats_valid_fractions_check CHECK (pred.check_all_jsonb_values_are_valid_stat_fractions(other_stats_fractions)),
+    ADD COLUMN metadata JSONB DEFAULT NULL;
+
+
+-- +goose StatementBegin
+CREATE OR REPLACE PROCEDURE pred.rollback_predicted_generation_partitions()
+LANGUAGE plpgsql
+AS $$
+DECLARE
+    partition_record RECORD;
+BEGIN
+    FOR partition_record IN
+        SELECT child.relname AS table_name
+        FROM pg_inherits
+        JOIN pg_class parent ON pg_inherits.inhparent = parent.oid
+        JOIN pg_class child ON pg_inherits.inhrelid = child.oid
+        JOIN pg_namespace nmsp_parent ON nmsp_parent.oid = parent.relnamespace
+        WHERE parent.relname = 'predicted_generation_values'
+          AND nmsp_parent.nspname = 'pred'
+    LOOP
+        EXECUTE format('
+            UPDATE pred.%I
+            SET target_time_utc = UUIDV7_EXTRACT_TIMESTAMP(forecast_uuid)::TIMESTAMP + MAKE_INTERVAL(mins => horizon_mins::INTEGER),
+	    other_stats_fractions = CASE WHEN p10_sip IS NOT NULL OR p90_sip IS NOT NULL THEN jsonb_strip_nulls(jsonb_build_object(''p10'', p10_sip::REAL / 30000, ''p90'', p90_sip::REAL / 30000))
+            ELSE NULL END;
+        ', partition_record.table_name);
+
+        EXECUTE format('ALTER TABLE pred.%I ALTER COLUMN target_time_utc SET NOT NULL;', partition_record.table_name);
+        EXECUTE format('ALTER TABLE pred.%I ADD PRIMARY KEY (forecast_uuid, target_time_utc);', partition_record.table_name);
+        
+        COMMIT;
+    END LOOP;
+END;
+$$;
+-- +goose StatementEnd
+
+CALL pred.rollback_predicted_generation_partitions();
+DROP PROCEDURE pred.rollback_predicted_generation_partitions;
+
+ALTER TABLE pred.predicted_generation_values
+    ALTER COLUMN target_time_utc SET NOT NULL,
+    ADD PRIMARY KEY (forecast_uuid, target_time_utc),
+    DROP COLUMN p10_sip, DROP COLUMN p90_sip;
+
+DROP TABLE IF EXISTS pred.predicted_generation_values_template;
+CREATE TABLE pred.predicted_generation_values_template (
+    horizon_mins SMALLINT NOT NULL,
+    CONSTRAINT horizon_mins_nonnegative_check CHECK (horizon_mins >= 0),
+    CONSTRAINT horizon_mins_fiveminutely_check CHECK (horizon_mins % 5 = 0),
+    p50_sip SMALLINT NOT NULL,
+    CONSTRAINT p50_sip_nonnegative_check CHECK (p50_sip >= 0),
+    target_time_utc TIMESTAMP NOT NULL,
+    forecast_uuid UUID NOT NULL REFERENCES pred.forecasts (forecast_uuid) ON DELETE CASCADE ON UPDATE CASCADE,
+    metadata JSONB DEFAULT NULL CONSTRAINT metadata_nullifempty CHECK (metadata IS NULL OR metadata != '{}'),
+    other_stats_fractions JSONB DEFAULT NULL CONSTRAINT other_stats_nullifempty CHECK (other_stats_fractions IS NULL OR other_stats_fractions != '{}'),
+    CONSTRAINT other_stats_valid_fractions_check CHECK (pred.check_all_jsonb_values_are_valid_stat_fractions(other_stats_fractions)),
+    PRIMARY KEY (forecast_uuid, target_time_utc)
+);
+
+ANALYZE pred.predicted_generation_values;
diff --git a/internal/server/postgres/sql/queries/predictions.sql b/internal/server/postgres/sql/queries/predictions.sql
index 0974373..51b1aca 100644
--- a/internal/server/postgres/sql/queries/predictions.sql
+++ b/internal/server/postgres/sql/queries/predictions.sql
@@ -123,9 +123,9 @@ WHERE forecast_uuid IN (SELECT forecast_uuid FROM forecasts_to_delete);
  * with 0 representing 0% and 30000 representing 100% of capacity.
  */
 INSERT INTO pred.predicted_generation_values (
-    horizon_mins, p50_sip, forecast_uuid, target_time_utc, other_stats_fractions, metadata
+    horizon_mins, p50_sip, p10_sip, p90_sip, forecast_uuid
 ) VALUES (
-    $1, $2, $3, $4, $5, $6
+    $1, $2, $3, $4, $5
 );
 
 -- name: ListPredictionsForForecasts :many
@@ -153,11 +153,15 @@ SELECT
     mf.forecaster_version,
     f.created_at_utc,
     pg.horizon_mins,
+    pg.p10_sip,
     pg.p50_sip,
-    pg.other_stats_fractions,
+    pg.p90_sip,
     sv.capacity_watts,
+    f.metadata,
     UUIDV7_EXTRACT_TIMESTAMP(f.forecast_uuid)::TIMESTAMP AS init_time_utc,
-    COALESCE(pg.metadata || f.metadata, pg.metadata, f.metadata) AS metadata
+    (
+        UUIDV7_EXTRACT_TIMESTAMP(pg.forecast_uuid)::TIMESTAMP + MAKE_INTERVAL(mins => pg.horizon_mins::INTEGER)
+    )::TIMESTAMP AS target_time_utc
 FROM pred.forecasts AS f
     INNER JOIN matched_forecasters AS mf USING (forecaster_id)
     INNER JOIN pred.predicted_generation_values AS pg
@@ -169,7 +173,8 @@ FROM pred.forecasts AS f
         FROM loc.sources_mv AS s
         WHERE s.geometry_uuid = f.geometry_uuid
             AND s.source_type_id = f.source_type_id
-            AND s.sys_period @> pg.target_time_utc
+            AND s.sys_period
+            @> (UUIDV7_EXTRACT_TIMESTAMP(pg.forecast_uuid)::TIMESTAMP + MAKE_INTERVAL(mins => pg.horizon_mins::INTEGER))
         LIMIT 1
     ) AS sv ON TRUE
 WHERE f.geometry_uuid = sqlc.arg(geometry_uuid)::UUID
@@ -256,29 +261,39 @@ WITH allowed_forecasts_overlapping_window AS (
         )
 ),
 winning_predictions AS (
-    SELECT DISTINCT ON (pg.target_time_utc)
-        pg.target_time_utc,
+    SELECT DISTINCT ON (
+        UUIDV7_EXTRACT_TIMESTAMP(pg.forecast_uuid)::TIMESTAMP + MAKE_INTERVAL(mins => pg.horizon_mins::INTEGER)
+    )
         fow.forecast_uuid,
         fow.init_time_utc,
         fow.created_at_utc,
         fow.geometry_uuid,
         fow.source_type_id,
         pg.horizon_mins,
+        pg.p10_sip,
         pg.p50_sip,
-        pg.other_stats_fractions,
-        COALESCE(pg.metadata || fow.metadata, pg.metadata, fow.metadata) AS metadata
+        pg.p90_sip,
+        fow.metadata,
+        (
+            UUIDV7_EXTRACT_TIMESTAMP(pg.forecast_uuid)::TIMESTAMP + MAKE_INTERVAL(mins => pg.horizon_mins::INTEGER)
+        )::TIMESTAMP AS target_time_utc
     FROM allowed_forecasts_overlapping_window AS fow
         INNER JOIN pred.predicted_generation_values AS pg USING (forecast_uuid)
-    WHERE pg.target_time_utc BETWEEN sqlc.arg(start_timestamp_utc)::TIMESTAMP AND sqlc.arg(end_timestamp_utc)::TIMESTAMP
-        AND pg.horizon_mins >= sqlc.arg(horizon_mins)::INTEGER
+    WHERE (
+        UUIDV7_EXTRACT_TIMESTAMP(pg.forecast_uuid)::TIMESTAMP + MAKE_INTERVAL(mins => pg.horizon_mins::INTEGER)
+    ) BETWEEN sqlc.arg(start_timestamp_utc)::TIMESTAMP AND sqlc.arg(end_timestamp_utc)::TIMESTAMP
+    AND pg.horizon_mins >= sqlc.arg(horizon_mins)::INTEGER
     -- Sorting by decreasing init time ensures the DISTINCT captures the lowest allowed horizon
-    ORDER BY pg.target_time_utc ASC, fow.init_time_utc DESC
+    ORDER BY
+        (UUIDV7_EXTRACT_TIMESTAMP(pg.forecast_uuid)::TIMESTAMP + MAKE_INTERVAL(mins => pg.horizon_mins::INTEGER)) ASC,
+        fow.init_time_utc DESC
 )
 SELECT
     wp.horizon_mins,
+    wp.p10_sip,
     wp.p50_sip,
+    wp.p90_sip,
     wp.target_time_utc,
-    wp.other_stats_fractions,
     wp.metadata,
     wp.init_time_utc,
     wp.created_at_utc,
@@ -343,22 +358,24 @@ SELECT
     laf.geometry_uuid,
     laf.source_type_id,
     pg.horizon_mins,
+    pg.p10_sip,
     pg.p50_sip,
-    pg.target_time_utc,
+    pg.p90_sip,
     laf.created_at_utc,
     laf.init_time_utc,
-    pg.other_stats_fractions,
     sv.capacity_watts,
     sv.latitude,
     sv.longitude,
     sv.geometry_name,
-    COALESCE(pg.metadata || laf.metadata, pg.metadata, laf.metadata) AS metadata
+    laf.metadata,
+    sqlc.arg(target_timestamp_utc)::TIMESTAMP AS target_time_utc
 FROM latest_allowed_forecast_per_location AS laf
     INNER JOIN pred.predicted_generation_values AS pg USING (forecast_uuid)
     INNER JOIN loc.sources_mv AS sv USING (geometry_uuid, source_type_id)
 WHERE
-    pg.target_time_utc = sqlc.arg(target_timestamp_utc)::TIMESTAMP
-    AND sv.sys_period @> pg.target_time_utc;
+    (UUIDV7_EXTRACT_TIMESTAMP(pg.forecast_uuid)::TIMESTAMP + MAKE_INTERVAL(mins => pg.horizon_mins::INTEGER))
+    = sqlc.arg(target_timestamp_utc)::TIMESTAMP
+    AND sv.sys_period @> sqlc.arg(target_timestamp_utc)::TIMESTAMP;
 
 -- name: GetWeekAverageDeltasForLocations :many
 /* GetWeekAverageDeltasForLocations retrieves the average deltas between predicted and observed generation values
@@ -385,9 +402,11 @@ relevant_predicted_values AS MATERIALIZED (
     SELECT
         rf.geometry_uuid,
         rf.source_type_id,
-        pg.target_time_utc,
         pg.horizon_mins,
-        pg.p50_sip
+        pg.p50_sip,
+        (
+            UUIDV7_EXTRACT_TIMESTAMP(pg.forecast_uuid)::TIMESTAMP + MAKE_INTERVAL(mins => pg.horizon_mins::INTEGER)
+        )::TIMESTAMP AS target_time_utc
     FROM relevant_forecasts AS rf
         INNER JOIN pred.predicted_generation_values AS pg USING (forecast_uuid)
     WHERE pg.forecast_uuid >= UUIDV7_BOUNDARY(sqlc.arg(pivot_timestamp)::TIMESTAMP - INTERVAL '8 days')
diff --git a/internal/server/postgres/testdata/seeding.sql b/internal/server/postgres/testdata/seeding.sql
index 895c260..a9d9de2 100644
--- a/internal/server/postgres/testdata/seeding.sql
+++ b/internal/server/postgres/testdata/seeding.sql
@@ -65,22 +65,23 @@ BEGIN
             TSRANGE(init_time_utc, init_time_utc + (forecast_len_mins * INTERVAL '1 minute'))
         FROM generated_data
         RETURNING forecast_uuid, init_time_utc
-    ),
-    static_json AS (
-        SELECT '{"source": "benchmark"}'::jsonb AS meta, '{"p10": 0.1, "p90": 0.9}'::jsonb AS stats
     )
     INSERT INTO pred.predicted_generation_values 
-        (horizon_mins, p50_sip, forecast_uuid, target_time_utc, metadata, other_stats_fractions)
-    SELECT gs.h, (random() * 30000)::SMALLINT, inf.forecast_uuid, 
-           inf.init_time_utc + (gs.h * INTERVAL '1 minute'), sj.meta, sj.stats
+        (horizon_mins, p50_sip, p10_sip, p90_sip, forecast_uuid)
+    SELECT 
+        gs.h, 
+        (random() * 30000)::SMALLINT,
+        3000::SMALLINT,
+        27000::SMALLINT,
+        inf.forecast_uuid
     FROM inserted_forecasts inf
-    CROSS JOIN static_json sj
     CROSS JOIN LATERAL generate_series(0, forecast_len_mins - pgv_res_mins, pgv_res_mins) AS gs(h)
     ORDER BY inf.init_time_utc ASC;
 
     -- Spoof the table size so Postgres uses indexes rather than seq scan in testing
     UPDATE pg_class SET reltuples = 346000000, relpages = 5000000 WHERE relname = 'predicted_generation_values';
-    UPDATE pg_class SET reltuples = 346000000, relpages = 5000000 WHERE relname = 'predicted_generation_values_forecast_uuid_idx';
+    UPDATE pg_class SET reltuples = 346000000, relpages = 5000000 WHERE relname = 'predicted_generation_values_pkey';
+    
     REFRESH MATERIALIZED VIEW loc.sources_mv;
     
     RETURN QUERY SELECT target_locations * (history_window_mins / forecast_freq_mins) * (forecast_len_mins / pgv_res_mins), geo_list;
diff --git a/proto/ocf/dp/dp-data.messages.proto b/proto/ocf/dp/dp-data.messages.proto
index edcf2ba..b833e7d 100644
--- a/proto/ocf/dp/dp-data.messages.proto
+++ b/proto/ocf/dp/dp-data.messages.proto
@@ -318,6 +318,7 @@ message ListForecastersResponse {
 
 message CreateForecastRequest {
   message ForecastValue {
+    reserved 4;
     uint32 horizon_mins = 1;
     float p50_fraction = 2 [
       (buf.validate.field).float.gte = 0,
@@ -328,6 +329,9 @@ message CreateForecastRequest {
     map<string, float> other_statistics_fractions = 3 [
       (buf.validate.field).map.min_pairs = 0,
       (buf.validate.field).map.max_pairs = 20,
+      (buf.validate.field).map.keys = {
+           string: {in: ["p10", "p90"]}
+      },
       (buf.validate.field).map.values = {
         float: {
           gte: 0.0,
@@ -336,7 +340,6 @@ message CreateForecastRequest {
         }
       }
     ];
-    optional google.protobuf.Struct metadata = 4;
   }
 
   Forecaster forecaster = 1 [