diff -r 38eee3346e87 trytond/trytond/modules/stock/move.py
--- a/trytond/trytond/modules/stock/move.py	Fri Jul 14 13:23:56 2017 +0200
+++ b/trytond/trytond/modules/stock/move.py	Fri Jul 14 13:35:06 2017 +0200
@@ -675,7 +675,12 @@

     @classmethod
     def write(cls, *args):
+        pool = Pool()
+        Product = pool.get('product.product')
+        Uom = pool.get('product.uom')
+
         actions = iter(args)
+        args = []
         for moves, values in zip(actions, actions):
             vals_set = set(values)
             if cls._deny_modify_assigned & vals_set:
@@ -687,6 +692,27 @@
                     if move.state in ('done', 'cancel'):
                         cls.raise_user_error('modify_done_cancel',
                             (move.rec_name,))
+            if set(['quantity', 'uom', 'product']) & vals_set:
+                int_qty2moves = {}
+                for move in moves:
+                    uom = values.get('uom', move.uom)
+                    if not isinstance(uom, Uom):
+                        uom = Uom(uom)
+                    product = values.get('product', move.product)
+                    if not isinstance(product, Uom):
+                        product = Product(product)
+                    internal_quantity = cls._get_internal_quantity(
+                        values.get('quantity', move.quantity),
+                        uom,
+                        product)
+                    int_qty2moves.setdefault(
+                        internal_quantity, []).append(move)
+                for int_qty, int_qty_moves in int_qty2moves.iteritems():
+                    new_values = values.copy()
+                    new_values['internal_quantity'] = int_qty
+                    args.extend((int_qty_moves, new_values))
+            else:
+                args.extend((moves, values))

         super(Move, cls).write(*args)

@@ -694,15 +720,6 @@
         for moves, values in zip(actions, actions):
             if any(f not in cls._allow_modify_closed_period for f in values):
                 cls.check_period_closed(moves)
-            for move in moves:
-                internal_quantity = cls._get_internal_quantity(move.quantity,
-                        move.uom, move.product)
-                if (internal_quantity != move.internal_quantity
-                        and internal_quantity
-                        != values.get('internal_quantity')):
-                    cls.write([move], {
-                            'internal_quantity': internal_quantity,
-                            })

     @classmethod
     def delete(cls, moves):
diff -r 38eee3346e87 trytond/trytond/modules/stock/shipment.py
--- a/trytond/trytond/modules/stock/shipment.py	Fri Jul 14 13:23:56 2017 +0200
+++ b/trytond/trytond/modules/stock/shipment.py	Fri Jul 14 13:35:06 2017 +0200
@@ -1241,18 +1241,26 @@
         Set planned date of moves for the shipments
         '''
         Move = Pool().get('stock.move')
+        to_write = []
         for shipment in shipments:
             outgoing_date, inventory_date = shipment._move_planned_date
-            Move.write([x for x in shipment.outgoing_moves
+            out_moves_to_write = [x for x in shipment.outgoing_moves
                     if (x.state not in ('assigned', 'done', 'cancel')
-                        and x.planned_date != outgoing_date)], {
-                    'planned_date': outgoing_date,
-                    })
-            Move.write([x for x in shipment.inventory_moves
+                        and x.planned_date != outgoing_date)]
+            if out_moves_to_write:
+                to_write.extend((out_moves_to_write, {
+                        'planned_date': outgoing_date,
+                        }))
+
+            inv_moves_to_write = [x for x in shipment.inventory_moves
                     if (x.state not in ('assigned', 'done', 'cancel')
-                        and x.planned_date != inventory_date)], {
-                    'planned_date': inventory_date,
-                    })
+                        and x.planned_date != inventory_date)]
+            if inv_moves_to_write:
+                to_write.extend((inv_moves_to_write, {
+                        'planned_date': inventory_date,
+                        }))
+        if to_write:
+            Move.write(*to_write)

     @classmethod
     def create(cls, vlist):