diff --git a/tests/domain/sap10_calculator/rdsap/test_cert_to_inputs.py b/tests/domain/sap10_calculator/rdsap/test_cert_to_inputs.py
index 17edfabd..8aa84a85 100644
--- a/tests/domain/sap10_calculator/rdsap/test_cert_to_inputs.py
+++ b/tests/domain/sap10_calculator/rdsap/test_cert_to_inputs.py
@@ -5690,7 +5690,10 @@ def test_mid_floor_flat_dwelling_type_zeroes_floor_and_roof_heat_transmission()
     # Arrange — A "Mid-floor flat" has party floor (downstairs flat) and
     # party ceiling (upstairs flat). The mapper must wire DwellingExposure
     # to suppress both channels so the HLC matches what RdSAP-driven
-    # assessor software produces.
+    # assessor software produces. A genuine mid-floor flat lodges
+    # roof_construction=7 ("dwelling above") — the party-ceiling code —
+    # NOT an external-roof construction (the default 4 = exposed pitched
+    # roof, which `_cert_lodges_exposed_roof` now reads as top-floor).
     epc = make_minimal_sap10_epc(
         total_floor_area_m2=_TYPICAL_TFA_M2,
         habitable_rooms_count=4,
@@ -5698,6 +5701,7 @@ def test_mid_floor_flat_dwelling_type_zeroes_floor_and_roof_heat_transmission()
         dwelling_type="Mid-floor flat",
         sap_building_parts=[
             make_building_part(
+                roof_construction=7,  # "dwelling above" — party ceiling
                 floor_dimensions=[
                     make_floor_dimension(total_floor_area_m2=_TYPICAL_TFA_M2, floor=0),
                 ],
@@ -5718,6 +5722,49 @@ def test_mid_floor_flat_dwelling_type_zeroes_floor_and_roof_heat_transmission()
     assert inputs.heat_transmission.walls_w_per_k > 0
 
 
+def test_mid_floor_label_with_exposed_roof_element_exposes_roof() -> None:
+    # Arrange — gov-API certs lodge `dwelling_type` as the raw assessor
+    # label, which can contradict the lodged fabric. Property 715363
+    # (uprn 6027561) and its sibling 715395 (6027563) lodge
+    # dwelling_type="Mid-floor flat" yet carry a real exposed flat roof
+    # (roof_construction=1, "Flat", with lodged insulation) over a
+    # "(another dwelling below)" floor — i.e. they are TOP-floor flats
+    # mislabelled mid-floor. Keying roof exposure on the label alone
+    # dropped the roof heat-loss term, under-reading space-heating demand
+    # ~32% and over-reading SAP +7 (calc 81 vs lodged 74). The correctly
+    # labelled top-floor sibling 715871 (6027574), same block + same flat
+    # roof, already computes the lodged 74 — the ground truth here.
+    #
+    # The lodged roof element is the authoritative signal: an assessor
+    # only lodges a non-party roof_construction (anything but 7 = "dwelling
+    # above") when the roof is a heat-loss surface.
+    epc = make_minimal_sap10_epc(
+        total_floor_area_m2=_TYPICAL_TFA_M2,
+        habitable_rooms_count=4,
+        region_code="1",
+        dwelling_type="Mid-floor flat",
+        sap_building_parts=[
+            make_building_part(
+                roof_construction=1,  # Flat — a genuine exposed roof
+                floor_dimensions=[
+                    make_floor_dimension(total_floor_area_m2=_TYPICAL_TFA_M2, floor=0),
+                ],
+            ),
+        ],
+        sap_heating=make_sap_heating(
+            main_heating_details=[_gas_boiler_detail(sap_main_heating_code=102)],
+        ),
+    )
+
+    # Act
+    inputs = cert_to_inputs(epc)
+
+    # Assert — the floor stays party (dwelling below) but the lodged
+    # exposed roof is honoured, matching the top-floor sibling.
+    assert inputs.heat_transmission.floor_w_per_k == 0.0
+    assert inputs.heat_transmission.roof_w_per_k > 0
+
+
 def test_top_floor_flat_keeps_roof_drops_floor() -> None:
     # Arrange — Top-floor flat: party floor, external roof.
     epc = make_minimal_sap10_epc(