diff --git a/applications/audit_generator/Master Sero Template - Data Extraction.xlsx b/applications/audit_generator/Master Sero Template - Data Extraction.xlsx
index 2416b11f2..15bc8d3ab 100644
Binary files a/applications/audit_generator/Master Sero Template - Data Extraction.xlsx and b/applications/audit_generator/Master Sero Template - Data Extraction.xlsx differ
diff --git a/domain/magicplan/ventilation_audit.py b/domain/magicplan/ventilation_audit.py
index 71dc2f0d9..74fc66e1f 100644
--- a/domain/magicplan/ventilation_audit.py
+++ b/domain/magicplan/ventilation_audit.py
@@ -11,7 +11,7 @@ from domain.magicplan.models import Door, Plan, Room, Window
 
 _DATA_START_ROW = 6
 _MAX_ROWS = 50
-_DOOR_AREA_COL = "T"
+_DOOR_AREA_COL = "U"
 _DOOR_AREA_CF_RANGE = f"{_DOOR_AREA_COL}{_DATA_START_ROW}:{_DOOR_AREA_COL}{_DATA_START_ROW + _MAX_ROWS - 1}"
 _Y_THRESHOLD = 7600
 _DOOR_AREA_HEADER = CellRichText(
@@ -87,16 +87,16 @@ def populate_sheet(sheet: Any, plan: Plan) -> None:
         pct = vent.pct_openable if vent else None
         _write_cell(sheet, row, "L", (pct / 100) if pct is not None else 0)
         # M = formula =I*L — do not write
-        _write_cell(sheet, row, "N", vent.num_trickle_vents if vent else 0)
-        _write_cell(sheet, row, "O", vent.trickle_vent_area_mm2 if vent else 0)
-        # P = unused gap — do not write
+        _write_cell(sheet, row, "N", vent.trickle_vent_area_mm2 if vent else 0)
+        _write_cell(sheet, row, "O", vent.num_trickle_vents if vent else 0)
+        # P = formula =N*O — do not write
 
     for i, (room_name, door) in enumerate(doors):
         row = _DATA_START_ROW + i
         vent = door.ventilation
-        _write_cell(sheet, row, "Q", room_name)
-        _write_cell(sheet, row, "R", door.width_mm)
-        _write_cell(sheet, row, "S", vent.undercut_mm if vent else 0)
-        # T = formula =R*S — do not write
+        _write_cell(sheet, row, "R", room_name)
+        _write_cell(sheet, row, "S", door.width_mm)
+        _write_cell(sheet, row, "T", vent.undercut_mm if vent else 0)
+        # U = formula =S*T — do not write
 
     _apply_column_y_formatting(sheet)
diff --git a/tests/domain/magicplan/test_ventilation_audit.py b/tests/domain/magicplan/test_ventilation_audit.py
index 6be6275fd..6ebb39362 100644
--- a/tests/domain/magicplan/test_ventilation_audit.py
+++ b/tests/domain/magicplan/test_ventilation_audit.py
@@ -135,7 +135,7 @@ def test_writes_window_opening_data_to_columns_J_K_L() -> None:
     assert sheet["L6"].value == pytest.approx(0.5)
 
 
-def test_writes_trickle_vent_count_to_N_and_total_area_to_O() -> None:
+def test_writes_trickle_vent_data_to_columns_N_and_O() -> None:
     # Arrange
     plan = _make_plan(num_rooms=1, num_windows_per_room=1, num_doors_per_room=0)
     sheet = _blank_sheet()
@@ -144,11 +144,11 @@ def test_writes_trickle_vent_count_to_N_and_total_area_to_O() -> None:
     populate_sheet(sheet, plan)
 
     # Assert
-    assert sheet["N6"].value == 2
-    assert sheet["O6"].value == 1000
+    assert sheet["N6"].value == 1000
+    assert sheet["O6"].value == 2
 
 
-def test_writes_door_room_name_to_column_Q() -> None:
+def test_writes_door_room_name_to_column_R() -> None:
     # Arrange
     plan = _make_plan(num_rooms=1, num_windows_per_room=0, num_doors_per_room=1)
     sheet = _blank_sheet()
@@ -157,10 +157,10 @@ def test_writes_door_room_name_to_column_Q() -> None:
     populate_sheet(sheet, plan)
 
     # Assert
-    assert sheet["Q6"].value == "Room 0"
+    assert sheet["R6"].value == "Room 0"
 
 
-def test_writes_door_dimensions_to_columns_R_and_S() -> None:
+def test_writes_door_dimensions_to_columns_S_and_T() -> None:
     # Arrange
     plan = _make_plan(num_rooms=1, num_windows_per_room=0, num_doors_per_room=1)
     sheet = _blank_sheet()
@@ -169,8 +169,8 @@ def test_writes_door_dimensions_to_columns_R_and_S() -> None:
     populate_sheet(sheet, plan)
 
     # Assert
-    assert sheet["R6"].value == 800.0
-    assert sheet["S6"].value == 10.0
+    assert sheet["S6"].value == 800.0
+    assert sheet["T6"].value == 10.0
 
 
 def test_writes_zeros_when_window_has_no_ventilation() -> None:
@@ -186,8 +186,8 @@ def test_writes_zeros_when_window_has_no_ventilation() -> None:
     assert sheet["J6"].value == 0
     assert sheet["K6"].value == 0
     assert sheet["L6"].value == 0
-    assert sheet["N6"].value == 0  # count
-    assert sheet["O6"].value == 0  # total area
+    assert sheet["N6"].value == 0
+    assert sheet["O6"].value == 0
 
 
 def test_writes_zeros_when_door_has_no_ventilation() -> None:
@@ -200,7 +200,7 @@ def test_writes_zeros_when_door_has_no_ventilation() -> None:
     populate_sheet(sheet, plan)
 
     # Assert
-    assert sheet["S6"].value == 0
+    assert sheet["T6"].value == 0
 
 
 _TEMPLATE_PATH = (
@@ -220,4 +220,4 @@ def test_real_template_survives_18_doors() -> None:
 
     populate_sheet(sheet, plan)
 
-    assert sheet["Q23"].value == "Room 17"
+    assert sheet["R23"].value == "Room 17"