diff --git a/sale.py b/sale.py
index ff5b6af611..1c976514be 100644
--- a/sale.py
+++ b/sale.py
@@ -1,7 +1,5 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
-from decimal import Decimal
-
 from trytond import backend
 from trytond.i18n import gettext
 from trytond.model import ModelView, Workflow, fields
@@ -9,7 +7,7 @@ from trytond.transaction import Transaction
 from trytond.pyson import Eval, If
 from trytond.pool import Pool, PoolMeta
 
-from trytond.modules.product import price_digits
+from trytond.modules.product import price_digits, round_price
 from trytond.modules.sale.exceptions import SaleConfirmError
 
 sale_shipment_cost_method = fields.Selection(
@@ -242,8 +240,7 @@ class Sale(metaclass=PoolMeta):
             if last_line.sequence is not None:
                 sequence = last_line.sequence + 1
 
-        shipment_cost = cost.quantize(
-            Decimal(1) / 10 ** SaleLine.shipment_cost.digits[1])
+        shipment_cost = round_price(cost)
         cost_line = SaleLine(
             sale=self,
             sequence=sequence,
@@ -254,8 +251,7 @@ class Sale(metaclass=PoolMeta):
             shipment_cost=shipment_cost,
             )
         cost_line.on_change_product()
-        cost_line.unit_price = cost.quantize(
-            Decimal(1) / 10 ** SaleLine.unit_price.digits[1])
+        cost_line.unit_price = round_price(cost)
         cost_line.amount = cost_line.on_change_with_amount()
         return cost_line
 
@@ -269,8 +265,7 @@ class Sale(metaclass=PoolMeta):
                 with Transaction().set_context(
                         shipment.get_carrier_context()):
                     cost, currency_id = self.carrier.get_sale_price()
-                cost = cost.quantize(
-                    Decimal(1) / 10 ** Shipment.cost.digits[1])
+                cost = round_price(cost)
                 Shipment.write([shipment], {
                         'carrier': self.carrier.id,
                         'cost': cost,
diff --git a/stock.py b/stock.py
index d6daf92ec5..822d89c46a 100644
--- a/stock.py
+++ b/stock.py
@@ -1,14 +1,12 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
-from decimal import Decimal
-
 from trytond.i18n import gettext
 from trytond.model import fields
 from trytond.pyson import Eval, Bool
 from trytond.transaction import Transaction
 from trytond.pool import Pool, PoolMeta
 
-from trytond.modules.product import price_digits
+from trytond.modules.product import price_digits, round_price
 from .exceptions import InvoiceShipmentCostError
 
 
@@ -56,8 +54,7 @@ class ShipmentOut(metaclass=PoolMeta):
             return
         with Transaction().set_context(self._get_carrier_context()):
             cost, currency_id = self.carrier.get_sale_price()
-        self.cost = cost.quantize(
-            Decimal(1) / 10 ** self.__class__.cost.digits[1])
+        self.cost = round_price(cost)
         self.cost_currency = currency_id
 
     def _get_cost_tax_rule_pattern(self):
@@ -91,8 +88,7 @@ class ShipmentOut(metaclass=PoolMeta):
             with Transaction().set_context(date=invoice.currency_date):
                 cost = Currency.compute(self.cost_currency, cost,
                     invoice.currency, round=False)
-        invoice_line.unit_price = cost.quantize(
-            Decimal(1) / 10 ** InvoiceLine.unit_price.digits[1])
+        invoice_line.unit_price = round_price(cost)
 
         taxes = []
         pattern = self._get_cost_tax_rule_pattern()
diff --git a/tryton.cfg b/tryton.cfg
index 51004ccadf..e7b28d5954 100644
--- a/tryton.cfg
+++ b/tryton.cfg
@@ -5,6 +5,7 @@ depends:
     carrier
     currency
     ir
+    product
     res
     sale
     stock