diff --git a/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000487.py b/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000487.py
index 3b9a87bd..2ba0d166 100644
--- a/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000487.py
+++ b/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000487.py
@@ -423,17 +423,30 @@ LINE_73_M_TOTAL_INTERNAL_GAINS_W: tuple[float, ...] = (
 # ============================================================================
 # §6 Solar gains — cert-derived inputs + expected outputs
 # ============================================================================
-# 2 wall windows, both South-facing, 2 glazing types (Manufacturer g⊥):
-#   "Double with unknown" g=0.76: S 0.77
-#   "Double between 2002" g=0.72: S 6.69
-# All PVC frame. No roof windows, no rooflights.
+# 5 wall windows mirroring the Summary §11 1:1, matching the Elmhurst
+# mapper's per-row extraction (mapper-vs-hand-built field-parity test).
+# All South-facing (orient=5) / PVC frame. Two glazing-type groups; per-
+# bp totals preserved (cascade-equivalent):
+#   g=0.76/U=2.8 (pre-2002): 0.77 m² (Ext1) — unchanged
+#   g=0.72/U=1.4 (post-2022): 6.69 m² total
+#     Main: 1.65 m² (1 row)
+#     Ext1: 5.04 m² split 2.16 + 1.53 + 1.35 (3 rows)
+# No roof windows, no rooflights.
 SECTION_6_VERTICAL_WINDOWS: tuple[SapWindow, ...] = (
-    # Windows 1 (PDF (27) U_eff=2.5180, raw U=2.8 pre-2002; g_⊥=0.76):
-    # area 0.77 m². make_window default u_value=2.8 matches.
-    make_window(orientation=5, width=0.77, height=1.0, solar_transmittance=0.76),
-    # Windows 2 (PDF (27) U_eff=1.3258, raw U=1.4 post-2022; g_⊥=0.72):
-    # area 6.69 m² (1.65 + 5.04). Replaced post-2022 → tighter U.
-    make_window(orientation=5, width=6.69, height=1.0, solar_transmittance=0.72, u_value=1.4),
+    # Window 1 on Ext1 (smaller pre-2002 window)
+    make_window(orientation=5, width=0.77, height=1.0, solar_transmittance=0.76,
+                u_value=2.8, window_location="1st Extension"),
+    # Windows 2 on Ext1 (post-2022 replacements)
+    make_window(orientation=5, width=2.16, height=1.0, solar_transmittance=0.72,
+                u_value=1.4, window_location="1st Extension"),
+    # Window 2 on Main (the only Main window — mapper places it between Ext1 rows)
+    make_window(orientation=5, width=1.65, height=1.0, solar_transmittance=0.72,
+                u_value=1.4, window_location="Main"),
+    # Two more post-2022 Ext1 windows
+    make_window(orientation=5, width=1.53, height=1.0, solar_transmittance=0.72,
+                u_value=1.4, window_location="1st Extension"),
+    make_window(orientation=5, width=1.35, height=1.0, solar_transmittance=0.72,
+                u_value=1.4, window_location="1st Extension"),
 )
 SECTION_6_ROOF_WINDOWS: tuple[RoofWindowInput, ...] = ()
 SECTION_6_ROOFLIGHTS: tuple[RooflightInput, ...] = ()