diff --git a/addons/mrp_byproduct/mrp_byproduct.py b/addons/mrp_byproduct/mrp_byproduct.py
index 97cb859196c..91ea997a2e4 100644
--- a/addons/mrp_byproduct/mrp_byproduct.py
+++ b/addons/mrp_byproduct/mrp_byproduct.py
@@ -92,18 +92,21 @@ class mrp_production(osv.osv):
                 continue
             for sub_product in production.bom_id.sub_products:
                 product_uom_factor = product_uom_obj._compute_qty(cr, uid, production.product_uom.id, production.product_qty, production.bom_id.product_uom.id)
+                qty1 = sub_product.product_qty
                 qty2 = production.product_uos and production.product_uos_qty or False
                 product_uos_factor = 0.0
                 if qty2 and production.bom_id.product_uos.id:
                     product_uos_factor = product_uom_obj._compute_qty(cr, uid, production.product_uos.id, production.product_uos_qty, production.bom_id.product_uos.id)
                 if sub_product.subproduct_type == 'variable':
+                    if production.product_qty:
+                        qty1 *= product_uom_factor / (production.bom_id.product_qty or 1.0)
                     if production.product_uos_qty:
                         qty2 *= product_uos_factor / (production.bom_id.product_uos_qty or 1.0)
                 data = {
                     'name': 'PROD:'+production.name,
                     'date': production.date_planned,
                     'product_id': sub_product.product_id.id,
-                    'product_uom_qty': production.product_qty,
+                    'product_uom_qty': qty1,
                     'product_uom': sub_product.product_uom.id,
                     'product_uos_qty': qty2,
                     'product_uos': production.product_uos and production.product_uos.id or False,