diff --git a/addons/point_of_sale/static/src/js/models.js b/addons/point_of_sale/static/src/js/models.js
index 81fb4432426..7b32d759987 100644
--- a/addons/point_of_sale/static/src/js/models.js
+++ b/addons/point_of_sale/static/src/js/models.js
@@ -1217,6 +1217,7 @@ class Orderline extends PosModel {
     getPackLotLinesToEdit(isAllowOnlyOneLot) {
         const currentPackLotLines = this.pack_lot_lines;
         let nExtraLines = Math.abs(this.quantity) - currentPackLotLines.length;
+        nExtraLines = Math.ceil(nExtraLines);
         nExtraLines = nExtraLines > 0 ? nExtraLines : 1;
         const tempLines = currentPackLotLines
             .map(lotLine => ({