diff --git a/sale.py b/sale.py
index a40c598..a88461f 100644
--- a/sale.py
+++ b/sale.py
@@ -20,6 +20,12 @@ class Sale(metaclass=PoolMeta):
         'get_amount')
     total_discount_cache = fields.Numeric(
         "Total Discount cache", digits='currency')
+    total_tip = fields.Function(
+        Monetary(
+            "Total Tip", digits='currency', currency='currency'),
+        'get_amount')
+    total_tip_cache = fields.Numeric(
+        "Total Tip cache", digits="currency")
 
     @classmethod
     def __setup__(cls):
@@ -42,6 +48,7 @@ class Sale(metaclass=PoolMeta):
         self.tax_amount = Decimal('0.0')
         self.total_amount = Decimal('0.0')
         self.total_discount = Decimal('0.0')
+        self.total_tip = Decimal('0.0')
 
         if self.lines:
             for line in self.lines:
@@ -52,6 +59,7 @@ class Sale(metaclass=PoolMeta):
             self.tax_amount = self.currency.round(self.tax_amount)
         self.total_amount = self.untaxed_amount + self.tax_amount
         if self.currency:
+            self.total_tip = self.currency.round(self.total_tip)
             self.total_discount = self.currency.round(self.total_discount)
             self.total_amount = self.currency.round(self.total_amount)
 
@@ -62,6 +70,7 @@ class Sale(metaclass=PoolMeta):
             sale.tax_amount_cache = sale.tax_amount
             sale.total_amount_cache = sale.total_amount
             sale.total_discount_cache = sale.total_discount
+            sale.total_tip_cache = sale.total_tip
         cls.save(sales)
 
     @classmethod
@@ -70,6 +79,7 @@ class Sale(metaclass=PoolMeta):
         tax_amount = {}
         total_amount = {}
         total_discount = {}
+        total_tip = {}
         if {'tax_amount', 'total_amount'} & set(names):
             compute_taxes = True
         else:
@@ -82,10 +92,10 @@ class Sale(metaclass=PoolMeta):
             if (sale.state in cls._states_cached
                     and sale.untaxed_amount_cache is not None
                     and sale.tax_amount_cache is not None
-                    and sale.total_amount_cache is not None
-                    and sale.total_discount_cache is not None):
+                    and sale.total_amount_cache is not None):
                 untaxed_amount[sale.id] = sale.untaxed_amount_cache
                 total_discount[sale.id] = sale.total_discount_cache
+                total_tip[sale.id] = sale.total_tip_cache
                 if compute_taxes:
                     tax_amount[sale.id] = sale.tax_amount_cache
                     total_amount[sale.id] = sale.total_amount_cache
@@ -94,8 +104,16 @@ class Sale(metaclass=PoolMeta):
                     (line.amount for line in sale.lines
                         if line.type == 'line'), Decimal(0)), 2)
                 total_discount[sale.id] = round(sum(
-                    (line.discount_amount for line in sale.lines
-                        if line.type == 'line'), Decimal(0)), 2)
+                    (line.discount_amount * Decimal(
+                        line.quantity) for line in sale.lines
+                        if line.discount_amount and line.type == 'line'
+                     ), Decimal(0)), 2)
+                total_tip[sale.id] = round(
+                    sum((
+                        line.amount for line in sale.lines
+                        if line.product and line.product.tip and (
+                                line.type == 'line')
+                    ), Decimal(0)), 2)
                 if compute_taxes:
                     tax_amount[sale.id] = sale.get_tax_amount()
                     total_amount[sale.id] = (
@@ -106,7 +124,8 @@ class Sale(metaclass=PoolMeta):
             'tax_amount': tax_amount,
             'total_amount': total_amount,
             'total_discount': total_discount,
-        }
+            'total_tip': total_tip
+            }
         for key in list(result.keys()):
             if key not in names:
                 del result[key]
@@ -149,6 +168,7 @@ class Sale(metaclass=PoolMeta):
         data = {}
         shop = Shop.search([('id', '=', ctx["shop"])])[0]
         data["shop_name"] = shop.name
+        data["shop_nit"] = shop.company.party.tax_identifier.code
         data["shop_address"] = shop.address.street
         data['invoice'] = cls.get_invoice(record)
         data["party"] = record.party.name
@@ -172,6 +192,7 @@ class Sale(metaclass=PoolMeta):
         data["total_discount"] = str(round(record.total_discount, 2))
         data["untaxed_amount"] = str(record.untaxed_amount)
         data["tax_amount"] = str(record.tax_amount)
+        data["total_tip"] = str(record.total_tip)
         data["total"] = str(record.total_amount)
         data["state"] = \
             "SUBTOTAL" if record.state == "draft" else "CUENTA FINAL"
@@ -392,12 +413,13 @@ class Line(metaclass=PoolMeta):
     @fields.depends('product', 'unit', 'sale',
                     '_parent_sale.party', '_parent_sale.invoice_party',
                     '_parent_sale.pizza_number',
-                    '_parent_product.pizza',
+                    '_parent_product.template',
+                    '_parent_product._parent_template.pizza',
                     methods=['compute_taxes', 'compute_unit_price',
                              'on_change_with_amount'])
     def on_change_product(self):
         super(Line, self).on_change_product()
-        if self.product and self.product.pizza:
+        if self.product and self.product.template.pizza:
             self.pizza = self.sale.pizza_number
             self.bought_pizza = True
         else: