diff --git a/src/town.h b/src/town.h
index 8d44e9ae1c..6454647a39 100644
--- a/src/town.h
+++ b/src/town.h
@@ -93,7 +93,7 @@ struct Town : TownPool::PoolItem<&_town_pool> {
 
 	/* Cargo production and acceptance stats. */
 	CargoTypes cargo_produced;       ///< Bitmap of all cargoes produced by houses in this town.
-	AcceptanceMatrix cargo_accepted; ///< Bitmap of cargoes accepted by houses for each 4*4 (really 6*6) map square of the town.
+	AcceptanceMatrix cargo_accepted; ///< Bitmap of cargoes accepted by houses for each 4*4 (really 12*12) map square of the town.
 	CargoTypes cargo_accepted_total; ///< NOSAVE: Bitmap of all cargoes accepted by houses in this town.
 	StationList stations_near;       ///< NOSAVE: List of nearby stations.
 
diff --git a/src/town_cmd.cpp b/src/town_cmd.cpp
index 4e7f609056..63682a0d5c 100644
--- a/src/town_cmd.cpp
+++ b/src/town_cmd.cpp
@@ -991,8 +991,8 @@ static void UpdateTownCargoesSingleGridArea(Town *t, TileIndex start, bool updat
 
 static void UpdateTownCargoesHouse(Town *t, TileIndex start, bool x_two_tiles, bool y_two_tiles, bool update_total = true)
 {
-	TileIndex lower = TileAddWrap(start, -1, -1);
-	TileIndex upper = TileAddWrap(start, x_two_tiles ? 2 : 1, y_two_tiles ? 2 : 1);
+	TileIndex lower = TileAddSaturating(start, -AcceptanceMatrix::GRID, -AcceptanceMatrix::GRID);
+	TileIndex upper = TileAddSaturating(start, AcceptanceMatrix::GRID + (x_two_tiles ? 1 : 0), AcceptanceMatrix::GRID + (y_two_tiles ? 1 : 0));
 	for (uint x = TileX(lower) & ~(AcceptanceMatrix::GRID - 1); x <= TileX(upper); x += AcceptanceMatrix::GRID) {
 		for (uint y = TileY(lower) & ~(AcceptanceMatrix::GRID - 1); y <= TileY(upper); y += AcceptanceMatrix::GRID) {
 			UpdateTownCargoesSingleGridArea(t, TileXY(x, y), false);