diff --git a/svc/product_series_auto_scheduler.go b/svc/product_series_auto_scheduler.go
index 01b7a2e..cd44224 100644
--- a/svc/product_series_auto_scheduler.go
+++ b/svc/product_series_auto_scheduler.go
@@ -109,6 +109,15 @@ func productSeriesFallbackLogEnabled() bool {
 	return raw == "1" || raw == "true" || raw == "on" || raw == "yes"
 }
 
+func productSeriesFallbackOverrideExisting() bool {
+	// Default off: do not override existing (possibly manual) assignments.
+	raw := strings.TrimSpace(strings.ToLower(os.Getenv("PRODUCT_SERIES_FALLBACK_OVERRIDE_EXISTING")))
+	if raw == "" {
+		return false
+	}
+	return raw == "1" || raw == "true" || raw == "on" || raw == "yes"
+}
+
 func productSeriesFallbackCode() string {
 	code := strings.TrimSpace(os.Getenv("PRODUCT_SERIES_FALLBACK_SERIES_CODE"))
 	if code == "" {
@@ -505,9 +514,10 @@ func productSeriesApplyVariant(ctx context.Context, pg *sql.DB, v productSeriesA
 			return 0, 1, err
 		}
 		if fallbackID > 0 {
-			// Only apply fallback when the variant has no assignments yet.
-			var exists int
-			checkErr := pg.QueryRowContext(ctx, `
+			if !productSeriesFallbackOverrideExisting() {
+				// Only apply fallback when the variant has no assignments yet.
+				var exists int
+				checkErr := pg.QueryRowContext(ctx, `
 SELECT 1
 FROM zbggseri
 WHERE mmitem_id=$1
@@ -515,18 +525,23 @@ WHERE mmitem_id=$1
   AND (($3::bigint IS NULL AND dim3 IS NULL) OR dim3=$3::bigint)
 LIMIT 1
 `, mmitemID, dim1ID, nullableInt64ForAuto(dim3ID)).Scan(&exists)
-			if checkErr == nil {
-				if productSeriesFallbackLogEnabled() {
-					log.Printf("[ProductSeriesFallback] already_exists product=%s color=%s dim3=%s fallback=%s(%d)", strings.TrimSpace(v.ProductCode), strings.TrimSpace(v.ColorCode), strings.TrimSpace(v.Dim3Code), strings.TrimSpace(fallbackCode), fallbackID)
+				if checkErr == nil {
+					if productSeriesFallbackLogEnabled() {
+						log.Printf("[ProductSeriesFallback] already_exists product=%s color=%s dim3=%s fallback=%s(%d)", strings.TrimSpace(v.ProductCode), strings.TrimSpace(v.ColorCode), strings.TrimSpace(v.Dim3Code), strings.TrimSpace(fallbackCode), fallbackID)
+					}
+					// keep existing manual/previous assignment; nothing to do
+					return 0, 0, nil
+				}
+				if checkErr != nil && checkErr != sql.ErrNoRows {
+					return 0, 1, checkErr
 				}
-				// keep existing manual/previous assignment; nothing to do
-				return 0, 0, nil
-			}
-			if checkErr != nil && checkErr != sql.ErrNoRows {
-				return 0, 1, checkErr
 			}
 			if productSeriesFallbackLogEnabled() {
-				log.Printf("[ProductSeriesFallback] apply product=%s color=%s dim3=%s fallback=%s(%d)", strings.TrimSpace(v.ProductCode), strings.TrimSpace(v.ColorCode), strings.TrimSpace(v.Dim3Code), strings.TrimSpace(fallbackCode), fallbackID)
+				if productSeriesFallbackOverrideExisting() {
+					log.Printf("[ProductSeriesFallback] override_apply product=%s color=%s dim3=%s fallback=%s(%d)", strings.TrimSpace(v.ProductCode), strings.TrimSpace(v.ColorCode), strings.TrimSpace(v.Dim3Code), strings.TrimSpace(fallbackCode), fallbackID)
+				} else {
+					log.Printf("[ProductSeriesFallback] apply product=%s color=%s dim3=%s fallback=%s(%d)", strings.TrimSpace(v.ProductCode), strings.TrimSpace(v.ColorCode), strings.TrimSpace(v.Dim3Code), strings.TrimSpace(fallbackCode), fallbackID)
+				}
 			}
 			// Use the fallback series as the single selected rule.
 			selected = []productSeriesAutoRule{{SeriesID: fallbackID}}
@@ -834,14 +849,6 @@ func productSeriesResolveDimTokenID(ctx context.Context, pg *sql.DB, column stri
 		return 0, false, nil
 	}
 
-	// dimval3 tokens like "001" can map to different dim ids per product in this installation.
-	// Prefer per-mmitem inference from dfblob (src_id filter) to avoid global mk_dim_token_map mismatches.
-	if column == "dimval3" && mmitemID > 0 {
-		if inferred, ok := productSeriesInferDimIDFromImages(pg, mmitemID, column, tok); ok {
-			return inferred, true, nil
-		}
-	}
-
 	var id int64
 	err := pg.QueryRowContext(ctx, `SELECT dim_id FROM mk_dim_token_map WHERE dim_column=$1 AND token=$2`, column, tok).Scan(&id)
 	if err == nil {
@@ -851,8 +858,9 @@ func productSeriesResolveDimTokenID(ctx context.Context, pg *sql.DB, column stri
 		return 0, false, err
 	}
 
-	// Fallback: infer from dfblob filenames. For dimval3 do not persist globally.
-	if mmitemID > 0 {
+	// Fallback: infer from dfblob filenames.
+	// For dimval3, prefer token map as the source of truth when present; use image inference only when missing.
+	if column == "dimval3" && mmitemID > 0 {
 		if inferred, ok := productSeriesInferDimIDFromImages(pg, mmitemID, column, tok); ok {
 			return inferred, true, nil
 		}
diff --git a/svc/routes/product_series.go b/svc/routes/product_series.go
index b6da31c..76eab0e 100644
--- a/svc/routes/product_series.go
+++ b/svc/routes/product_series.go
@@ -361,11 +361,11 @@ LIMIT 1
 			row.MmitemID = mmitemByCode[row.ProductCode]
 			row.Dim1ID = dim1ByToken[row.ColorCode]
 			if row.Dim3Code != "" {
-				// dimval3 tokens can be ambiguous globally; prefer per-mmitem inference.
-				if inferred := inferDim3ForMmitem(row.MmitemID, row.Dim3Code); inferred > 0 {
+				// dimval3 can be ambiguous, but if mk_dim_token_map has a row we treat it as source of truth.
+				if v := dim3ByToken[row.Dim3Code]; v > 0 {
+					row.Dim3ID = v
+				} else if inferred := inferDim3ForMmitem(row.MmitemID, row.Dim3Code); inferred > 0 {
 					row.Dim3ID = inferred
-				} else {
-					row.Dim3ID = dim3ByToken[row.Dim3Code]
 				}
 			}
 			row.MappingReady = row.MmitemID > 0 && row.Dim1ID > 0 && (row.Dim3Code == "" || row.Dim3ID > 0)