diff --git a/addons/stock/models/stock_move.py b/addons/stock/models/stock_move.py
index 0dac3ad176d..20575ba9a8b 100644
--- a/addons/stock/models/stock_move.py
+++ b/addons/stock/models/stock_move.py
@@ -897,11 +897,13 @@ class StockMove(models.Model):
         assigned_moves = self.env['stock.move']
         partially_available_moves = self.env['stock.move']
         for move in self.filtered(lambda m: m.state in ['confirmed', 'waiting', 'partially_available']):
+            missing_reserved_uom_quantity = move.product_uom_qty - move.reserved_availability
+            missing_reserved_quantity = move.product_uom._compute_quantity(missing_reserved_uom_quantity, move.product_id.uom_id, rounding_method='HALF-UP')
             if move.location_id.should_bypass_reservation()\
                     or move.product_id.type == 'consu':
                 # create the move line(s) but do not impact quants
                 if move.product_id.tracking == 'serial' and (move.picking_type_id.use_create_lots or move.picking_type_id.use_existing_lots):
-                    for i in range(0, int(move.product_qty - move.reserved_availability)):
+                    for i in range(0, int(missing_reserved_quantity)):
                         self.env['stock.move.line'].create(move._prepare_move_line_vals(quantity=1))
                 else:
                     to_update = move.move_line_ids.filtered(lambda ml: ml.product_uom_id == move.product_uom and
@@ -912,16 +914,16 @@ class StockMove(models.Model):
                                                             not ml.package_id and
                                                             not ml.owner_id)
                     if to_update:
-                        to_update[0].product_uom_qty += move.product_qty - move.reserved_availability
+                        to_update[0].product_uom_qty += missing_reserved_uom_quantity
                     else:
-                        self.env['stock.move.line'].create(move._prepare_move_line_vals(quantity=move.product_qty - move.reserved_availability))
+                        self.env['stock.move.line'].create(move._prepare_move_line_vals(quantity=missing_reserved_quantity))
                 assigned_moves |= move
             else:
                 if not move.move_orig_ids:
                     if move.procure_method == 'make_to_order':
                         continue
                     # If we don't need any quantity, consider the move assigned.
-                    need = move.product_qty - move.reserved_availability
+                    need = missing_reserved_quantity
                     if float_is_zero(need, precision_rounding=move.product_id.uom_id.rounding):
                         assigned_moves |= move
                         continue
diff --git a/addons/stock/tests/test_move.py b/addons/stock/tests/test_move.py
index 422d61c2dbc..1ce26f22f1f 100644
--- a/addons/stock/tests/test_move.py
+++ b/addons/stock/tests/test_move.py
@@ -950,6 +950,27 @@ class StockMove(TransactionCase):
         move_partial._action_assign()
         self.assertEqual(move_partial.state, 'assigned')
 
+    def test_availability_9(self):
+        """ Test the assignment mechanism when the product quantity is increase
+        on a receipt move.
+        """
+        move_receipt = self.env['stock.move'].create({
+            'name': 'test_receipt_edit',
+            'location_id': self.supplier_location.id,
+            'location_dest_id': self.stock_location.id,
+            'product_id': self.product1.id,
+            'product_uom': self.uom_dozen.id,
+            'product_uom_qty': 1.0,
+        })
+
+        move_receipt._action_confirm()
+        move_receipt._action_assign()
+        self.assertEqual(move_receipt.state, 'assigned')
+        move_receipt.product_uom_qty = 3.0
+        move_receipt._action_assign()
+        self.assertEqual(move_receipt.state, 'assigned')
+        self.assertEqual(move_receipt.move_line_ids.product_uom_qty, 3)
+
     def test_unreserve_1(self):
         """ Check that unreserving a stock move sets the products reserved as available and
         set the state back to confirmed.