diff --git a/ChangeLog b/ChangeLog
index 1a15db6..ffe4994 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,11 @@
 Recent changes to the ets_fiberalloc package,
 in reverse chronological order:
 
+yet unreleased:
+  https://pfs-jira.naoj.org/jira/browse/FIBERALLOC-61
+  (Allow perturbation of target observation cost)
+
+
 - v3.5:
   https://pfs-jira.naoj.org/jira/browse/FIBERALLOC-59
   (add support for cobraOps parameter "brokenCobrasMargin")
diff --git a/ets_fiber_assigner/netflow.py b/ets_fiber_assigner/netflow.py
index 9e4632e..14fed64 100644
--- a/ets_fiber_assigner/netflow.py
+++ b/ets_fiber_assigner/netflow.py
@@ -264,7 +264,8 @@ def buildProblem(bench, targets, tpos, classdict, tvisit, vis_cost=None,
                  preassigned=None,
                  cobraSafetyMargin=0.,
                  cobraFeatureFlags=None,
-                 brokenCobrasMargin=0.):
+                 brokenCobrasMargin=0.,
+                 targetCostOffset=None):
     """Build the ILP problem for a given observation task
 
     Parameters
@@ -404,6 +405,10 @@ def buildProblem(bench, targets, tpos, classdict, tvisit, vis_cost=None,
         This is given as a fraction of "brokenCobrasRmax", i.e. the maximum
         patrol area radius of any broken Cobra.
         Useful values should be in the range [0;1].
+    targetCostOffset: np.ndarray(float), same size as "targets"
+        per-target perturbation of the overall cost function, if this target
+        is observed. Used to break degeneracies and guarantee reproducible
+        assignments.
 
     Returns
     =======
@@ -533,6 +538,8 @@ def buildProblem(bench, targets, tpos, classdict, tvisit, vis_cost=None,
                     f = prob.addVar(makeName("STC_T", TC, tgt.ID), tmp, 1)
                     T_i[tidx].append(f)
                     STC_o[TC].append(f)
+                    if targetCostOffset is not None and targetCostOffset[tidx] != 0:
+                        prob.cost += f*targetCostOffset[tidx]
                     if len(STC_o[TC]) == 1:  # freshly created
                         # Science Target class node to sink
                         f = prob.addVar(makeName("STC_sink", TC), 0, None)