diff --git a/modules/purchase_trade/fee.py b/modules/purchase_trade/fee.py
index 4b4beb7..d55784c 100755
--- a/modules/purchase_trade/fee.py
+++ b/modules/purchase_trade/fee.py
@@ -245,7 +245,9 @@ class Fee(ModelSQL,ModelView):
         elif self.mode == 'perqt':
             return self.price
         elif self.mode == 'ppack':
-            return self.price / self.unit.factor * self.get_unit().factor
+            unit  = self.get_unit()
+            if unit and self.unit:
+                return self.price / self.unit.factor * unit.factor
         elif self.mode == 'pprice' or self.mode == 'pcost':
             if self.line and self.price:
                 return round(self.price * Decimal(self.line.unit_price) / 100,4)
@@ -285,6 +287,8 @@ class Fee(ModelSQL,ModelView):
             #         sign = -1
             if self.mode == 'lumpsum':
                 return self.price * sign
+            elif self.mode == 'ppack':
+                return round(self.price * self.quantity,2)
             elif self.mode == 'perqt':
                 if self.shipment_in:
                     StockMove = Pool().get('stock.move')