diff --git a/datatypes/epc/domain/mapper.py b/datatypes/epc/domain/mapper.py
index 26b424e70..80a650515 100644
--- a/datatypes/epc/domain/mapper.py
+++ b/datatypes/epc/domain/mapper.py
@@ -986,7 +986,15 @@ class EpcPropertyDataMapper:
                 pv_battery_count=0,
                 wind_turbines_count=schema.sap_energy_source.wind_turbines_count or 0,
                 gas_smart_meter_present=False,
-                is_dwelling_export_capable=False,
+                # Top-level full-SAP export flag (SAP 10-era lodgements; None
+                # on the SAP 2012 family → False, unchanged). Appendix M1 zeroes
+                # the PV export credit without the flag, under-rating any
+                # export-capable PV cert (PRD #1435 WS3). `pv_connection` is NOT
+                # carried — the full-SAP enum disagrees with the RdSAP one the
+                # calculator's connection gate reads (see SapSchema17_1).
+                is_dwelling_export_capable=(
+                    schema.is_dwelling_export_capable == "true"
+                ),
                 wind_turbines_terrain_type=str(
                     schema.sap_energy_source.wind_turbine_terrain_type or ""
                 ),
diff --git a/datatypes/epc/schema/sap_schema_17_1.py b/datatypes/epc/schema/sap_schema_17_1.py
index e4f41d9e9..656a28b25 100644
--- a/datatypes/epc/schema/sap_schema_17_1.py
+++ b/datatypes/epc/schema/sap_schema_17_1.py
@@ -247,3 +247,13 @@ class SapSchema17_1:
     has_hot_water_cylinder: Optional[str] = None
     # Present for flat-type dwellings; absence means not a flat.
     sap_flat_details: Optional[SapFlatDetails] = None
+    # Top-level PV export-capability flag (lodged by the SAP 10-era full-SAP
+    # schemas; absent on the SAP 2012 family, where SEG export did not exist).
+    # SAP 10.2 Appendix M1 zeroes the PV export credit unless the dwelling is
+    # connected to an export-capable meter, so dropping the flag under-rates
+    # any export-capable PV cert (~3 SAP on cert 0380-3044-6070-2305-5925).
+    # The sibling top-level `pv_connection` is deliberately NOT parsed: the
+    # full-SAP enum disagrees with the RdSAP/gov-API one the calculator gates
+    # on (full-SAP certs lodge 1 with a PV credit included; RdSAP 1 = "not
+    # connected" = no credit), so carrying it across would zero real arrays.
+    is_dwelling_export_capable: Optional[str] = None
diff --git a/tests/domain/sap10_calculator/test_real_cert_sap_accuracy.py b/tests/domain/sap10_calculator/test_real_cert_sap_accuracy.py
index 5604b8015..70a93637b 100644
--- a/tests/domain/sap10_calculator/test_real_cert_sap_accuracy.py
+++ b/tests/domain/sap10_calculator/test_real_cert_sap_accuracy.py
@@ -303,11 +303,16 @@ _EXPECTATIONS: Final[tuple[RealCertExpectation, ...]] = (
     # the schema dropped at parse, so the Appendix-M generation credit was lost.
     # Carrying it (mapper `_sap_17_1_pv_arrays`) credits the generation and lifts
     # this flat 82→84, closing most of the gap to the lodged 85 the array explains.
+    # WAS 84 until the full-SAP export-capable mapping landed (PRD #1435 WS3):
+    # this cert lodges `is_dwelling_export_capable: true`, which the mapper
+    # hardcoded False, so Appendix M1 zeroed the array's export credit. Carrying
+    # the lodged flag restores it and the engine now reproduces the lodged 85
+    # EXACTLY — the last −1 was the missing export credit, not a methodology gap.
     RealCertExpectation(
         schema="SAP-Schema-19.1.0",
         sample="uprn_10096028301",
         cert_num="0390-3321-6060-2405-7985",
-        sap_score=84,
+        sap_score=85,
     ),
     # UPRN 10094615101 → cert 0380-3044-6070-2305-5925. SAP-Schema-19.1.0 — a
     # FULL-SAP TOP-FLOOR FLAT (2023 new build, St Leonards-on-Sea, TFA 76 m²,