diff --git a/tests/infrastructure/epc_client/test_sap_accuracy_corpus.py b/tests/infrastructure/epc_client/test_sap_accuracy_corpus.py
index aa05c9af..5f8d3669 100644
--- a/tests/infrastructure/epc_client/test_sap_accuracy_corpus.py
+++ b/tests/infrastructure/epc_client/test_sap_accuracy_corpus.py
@@ -95,8 +95,11 @@ _CORPUS = Path(
 # 67.3% -> 67.5% (MAE 1.020 -> 0.987). The follow-on `common_wall_*` Detailed-RR
 # surfaces (billed at main-wall U, deducted from the §3.10.1 residual) took the
 # 6-cert detailed-common-wall cohort 2.43 -> 1.25; corpus -> 67.6% (MAE 0.979).
+# The §3.9.2 Simplified Type-2 RR mapper (room_in_roof_type_2: gable quadratic +
+# common-wall L×(0.25+H), MIRRORING the worksheet-validated Summary path,
+# cross-mapper-parity-exact on cert 000565) -> 67.9% (MAE 0.959).
 _MIN_WITHIN_HALF_SAP = 0.67
-_MAX_SAP_MAE = 0.99
+_MAX_SAP_MAE = 0.97
 _MAX_CO2_MAE_TONNES = 0.35      # t CO2 / yr vs co2_emissions_current
 _MAX_PE_PER_M2_MAE = 16.0       # kWh / m2 / yr vs energy_consumption_current