diff --git a/domain/epc/property_overlays/main_heating_system_overlay.py b/domain/epc/property_overlays/main_heating_system_overlay.py
index 6d25d979c..243326cfd 100644
--- a/domain/epc/property_overlays/main_heating_system_overlay.py
+++ b/domain/epc/property_overlays/main_heating_system_overlay.py
@@ -185,14 +185,18 @@ _CONSERVATIVE_HEAT_PUMP_CONTROL = 2201
 _HEAT_NETWORK_CATEGORY = 6
 _HEAT_NETWORK_CODES = frozenset({301, 302, 303, 304})
 _COMMUNITY_BOILER_CODES = frozenset({301, 302, 303})
-# SAP Table 4e Group 3 heat-network control: 2301 ("flat rate charging, no
-# thermostatic control of room temperature") is the conservative default when
-# the landlord named only the scheme. It is never-over-crediting on BOTH axes
-# the control drives: the largest Group 3 temperature adjustment (+0.3 C, tied
-# with 2302) and the worst Table 4c(3) charging factors (space 1.10, DHW 1.05
-# — an unobserved charging arrangement is never assumed usage-linked). The
-# community mirror of storage 2401 / boiler 2101 / heat-pump 2201 (ADR-0053).
-_CONSERVATIVE_HEAT_NETWORK_CONTROL = 2301
+# SAP Table 4e Group 3 heat-network control: 2313 ("flat rate charging, room
+# thermostat and TRVs") is the default when the landlord named only the scheme
+# — a per-axis choice (ADR-0053, decided with Khalim). KIT axis: community
+# schemes skew modern and the portfolio's lodged community certs are
+# overwhelmingly thermostatted (modal 2306; none lodge 2301), so a room
+# thermostat + TRVs is the evidence-backed assumption (temperature adjustment
+# 0.0). CHARGING axis: flat rate (Table 4c(3) space 1.05 / DHW 1.05) — the
+# billing arrangement is scheme paperwork an override cannot see, so the
+# usage-linked credit (1.0/1.0) is never assumed. An assessor-OBSERVED Group 3
+# control on the cert is kept in preference to this default (the overlay sets
+# `keep_existing_heat_network_control`; the applicator honours it).
+_DEFAULT_HEAT_NETWORK_CONTROL = 2313
 _COMMUNITY_GAS_FUEL = 20
 
 # SAP Table 4c full boiler-control code: programmer + room thermostat + TRVs. The
@@ -324,7 +328,7 @@ def _control_for(code: int) -> Optional[int]:
     if code in _WET_HEAT_PUMP_CODES:
         return _CONSERVATIVE_HEAT_PUMP_CONTROL
     if code in _HEAT_NETWORK_CODES:
-        return _CONSERVATIVE_HEAT_NETWORK_CONTROL
+        return _DEFAULT_HEAT_NETWORK_CONTROL
     return None