diff --git a/domain/sap10_calculator/rdsap/cert_to_inputs.py b/domain/sap10_calculator/rdsap/cert_to_inputs.py
index 5f7c2310..fcf2ed75 100644
--- a/domain/sap10_calculator/rdsap/cert_to_inputs.py
+++ b/domain/sap10_calculator/rdsap/cert_to_inputs.py
@@ -412,15 +412,25 @@ SAP_10_2_SPEC_PRICES: Final[PriceTable] = PriceTable(
 )
 
 
-# SAP 10.2 Table 9 main_heating_control codes → control type (1/2/3).
+# SAP 10.2 Table 4e (page 171) main_heating_control codes → control type
+# (1/2/3 per Table 9 "Heating control type" column). Type drives the
+# elsewhere-zone off-hours pattern in Table 9: types 1+2 use (7, 8),
+# type 3 uses (9, 8) per footnote (b) "heating 0700-0900 and 1800-2300".
+#
 # Type 1: no time + temp control, or one but not both.
-# Type 2: programmer + room thermostat (+/− TRVs).
-# Type 3: time-and-temperature zone control (e.g. separate living-zone
-# programmer + thermostat).
+# Type 2: programmer + room thermostat (+/− TRVs); also bare TRV-class
+#         controls (2111 "TRVs and bypass", 2113 "Room thermostat and
+#         TRVs") — these were misclassified as type 3 pre-S0380.25 and
+#         pushed cert 0652 to +1.93 SAP / cert 6835 to +0.72.
+# Type 3: time-and-temperature zone control (separate living-zone
+#         schedule via plumbing/electrical arrangement or PCDB device).
 _CONTROL_TYPE_BY_CODE: Final[dict[int, int]] = {
     2101: 1, 2102: 1, 2103: 1, 2104: 1,
     2105: 2, 2106: 2, 2107: 2, 2108: 2, 2109: 2,
-    2110: 3, 2111: 3, 2112: 3, 2113: 3,
+    2110: 3,
+    2111: 2,  # TRVs and bypass — Table 4e row "2 0"
+    2112: 3,
+    2113: 2,  # Room thermostat and TRVs — Table 4e row "2 0"
 }
 
 
diff --git a/domain/sap10_calculator/rdsap/tests/test_cert_to_inputs.py b/domain/sap10_calculator/rdsap/tests/test_cert_to_inputs.py
index c1a0f59a..5f154fc1 100644
--- a/domain/sap10_calculator/rdsap/tests/test_cert_to_inputs.py
+++ b/domain/sap10_calculator/rdsap/tests/test_cert_to_inputs.py
@@ -707,11 +707,21 @@ def test_main_heating_control_code_maps_to_sap_control_type() -> None:
     type_1 = cert_to_inputs(_epc_with_control(2103))
     type_2 = cert_to_inputs(_epc_with_control(2106))
     type_3 = cert_to_inputs(_epc_with_control(2110))
+    # Slice S0380.25: SAP 10.2 Table 4e (page 171) classifies codes 2111
+    # ("TRVs and bypass") and 2113 ("Room thermostat and TRVs") as
+    # control type 2, NOT type 3 — they lack the time-zone control that
+    # type 3 requires. Mis-classifying these as type 3 swapped the
+    # elsewhere-zone off-hours from (7, 8) to (9, 8), under-counting MIT
+    # by ~0.67 °C → cert 0652 +1.93 SAP / cert 6835 +0.72 SAP.
+    type_2_via_2111 = cert_to_inputs(_epc_with_control(2111))
+    type_2_via_2113 = cert_to_inputs(_epc_with_control(2113))
 
     # Assert
     assert type_1.control_type == 1
     assert type_2.control_type == 2
     assert type_3.control_type == 3
+    assert type_2_via_2111.control_type == 2
+    assert type_2_via_2113.control_type == 2
 
 
 def test_off_peak_meter_routes_electric_costs_to_low_rate() -> None: