Sell no works to a dwelling already at the goal band 🟩

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

orchestration/modelling_orchestrator.py

@@ -491,10 +491,17 @@ def _objective_for(
 
 def _target_sap(scenario: Scenario) -> Optional[float]:
     """The SAP rating the Optimiser repairs toward — the floor of the goal
-    band for an INCREASING_EPC goal, else None (no SAP target)."""
+    band for an INCREASING_EPC goal, else None (no SAP target).
+
+    On the **continuous** scale, because that is the currency every figure the
+    Optimiser compares it against is in. The dwelling is in the goal band once
+    its *published* rating is, which happens half a point below the integer
+    floor — target the integer and a dwelling publishing at the floor reads as a
+    fraction short, and the Optimiser buys works toward a band it is already in
+    (#1654)."""
     if scenario.goal != PortfolioGoal.INCREASING_EPC.value:
         return None
-    return float(Epc(scenario.goal_value).sap_lower_bound())
+    return Epc(scenario.goal_value).sap_lower_bound_continuous()
 
 
 def _best_practice_key(option: MeasureOption) -> int:

tests/orchestration/test_modelling_goal_band_floor.py

@@ -40,3 +40,18 @@ def test_dwelling_published_at_the_goal_band_is_sold_no_works() -> None:
     # Assert — nothing to buy: the goal is already met.
     assert plan.measures == ()
     assert plan.cost_of_works == 0.0
+
+
+def test_dwelling_below_the_goal_band_is_still_taken_to_it() -> None:
+    # Arrange — the same cert with an uninsulated loft scores a continuous
+    # 37.349, published SAP 37: band F, genuinely short of band D. Lowering the
+    # target by half a point must not let the package stop short of the band.
+    below_band_d = _dwelling("loft_001431_before.pdf")
+
+    # Act
+    plan: Plan = run_modelling(below_band_d, goal_band="D", print_table=False)
+
+    # Assert — real works, and they carry the dwelling into band D.
+    assert plan.measures != ()
+    assert plan.cost_of_works > 0.0
+    assert plan.post_retrofit.sap_continuous >= 54.5