diff --git a/addons/point_of_sale/models/pos_order.py b/addons/point_of_sale/models/pos_order.py
index 3b2cc4f5839..acffb09f984 100644
--- a/addons/point_of_sale/models/pos_order.py
+++ b/addons/point_of_sale/models/pos_order.py
@@ -846,8 +846,8 @@ class PosOrderLine(models.Model):
                 raise UserError(_('You have to select a pricelist in the sale form.'))
             price = self.price_unit * (1 - (self.discount or 0.0) / 100.0)
             self.price_subtotal = self.price_subtotal_incl = price * self.qty
-            if (self.product_id.taxes_id):
-                taxes = self.product_id.taxes_id.compute_all(price, self.order_id.pricelist_id.currency_id, self.qty, product=self.product_id, partner=False)
+            if (self.tax_ids):
+                taxes = self.tax_ids.compute_all(price, self.order_id.pricelist_id.currency_id, self.qty, product=self.product_id, partner=False)
                 self.price_subtotal = taxes['total_excluded']
                 self.price_subtotal_incl = taxes['total_included']
 
diff --git a/addons/sale_coupon/models/sale_order.py b/addons/sale_coupon/models/sale_order.py
index 1652c5b70e8..106a1012601 100644
--- a/addons/sale_coupon/models/sale_order.py
+++ b/addons/sale_coupon/models/sale_order.py
@@ -140,9 +140,8 @@ class SaleOrder(models.Model):
 
     def _get_reward_values_discount(self, program):
         if program.discount_type == 'fixed_amount':
-            taxes = program.discount_line_product_id.taxes_id
-            if self.fiscal_position_id:
-                taxes = self.fiscal_position_id.map_tax(taxes)
+            product_taxes = program.discount_line_product_id.taxes_id.filtered(lambda tax: tax.company_id == self.company_id)
+            taxes = self.fiscal_position_id.map_tax(product_taxes)
             return [{
                 'name': _("Discount: %s", program.name),
                 'product_id': program.discount_line_product_id.id,
diff --git a/addons/sale_purchase/models/sale_order.py b/addons/sale_purchase/models/sale_order.py
index a9d6ae19abf..751135ebe49 100644
--- a/addons/sale_purchase/models/sale_order.py
+++ b/addons/sale_purchase/models/sale_order.py
@@ -230,9 +230,8 @@ class SaleOrderLine(models.Model):
             uom_id=self.product_id.uom_po_id
         )
         fpos = purchase_order.fiscal_position_id
-        taxes = fpos.map_tax(self.product_id.supplier_taxes_id)
-        if taxes:
-            taxes = taxes.filtered(lambda t: t.company_id.id == self.company_id.id)
+        supplier_taxes = self.product_id.supplier_taxes_id.filtered(lambda t: t.company_id.id == self.company_id.id)
+        taxes = fpos.map_tax(supplier_taxes)
 
         # compute unit price
         price_unit = 0.0