diff --git a/modules/account_invoice/invoice.py b/modules/account_invoice/invoice.py
index 466ab0a..418400a 100755
--- a/modules/account_invoice/invoice.py
+++ b/modules/account_invoice/invoice.py
@@ -565,6 +565,16 @@ class Invoice(Workflow, ModelSQL, ModelView, TaxableMixin, InvoiceReportMixin):
                 if rate:
                     return round(1/rate,6) or 1
 
+    def _compute_company_currency_amount(self, amount, date=None):
+        Currency = Pool().get('currency.currency')
+        if self.currency == self.company.currency:
+            return amount
+        if self.rate:
+            return self.company.currency.round(amount / self.rate)
+        with Transaction().set_context(date=date or self.currency_date):
+            return Currency.compute(
+                self.currency, amount, self.company.currency)
+
     @staticmethod
     def default_type():
         return Transaction().context.get('type', 'out')
@@ -1900,6 +1910,8 @@ class Invoice(Workflow, ModelSQL, ModelView, TaxableMixin, InvoiceReportMixin):
         
         moves = []
         for invoice in invoices:
+            if invoice.currency != invoice.company.currency and not invoice.rate:
+                invoice.rate = invoice.get_selected_rate()
             move = invoice.get_move()
             if move != invoice.move:
                 invoice.move = move
@@ -3199,7 +3211,6 @@ class InvoiceLine(sequence_ordered(), ModelSQL, ModelView, TaxableMixin):
 
     def _compute_taxes(self):
         pool = Pool()
-        Currency = pool.get('currency.currency')
         TaxLine = pool.get('account.tax.line')
 
         tax_lines = []
@@ -3208,11 +3219,7 @@ class InvoiceLine(sequence_ordered(), ModelSQL, ModelView, TaxableMixin):
         taxes = self._get_taxes().values()
         for tax in taxes:
             amount = tax['base']
-            with Transaction().set_context(
-                    date=self.invoice.currency_date):
-                amount = Currency.compute(
-                    self.invoice.currency, amount,
-                    self.invoice.company.currency)
+            amount = self.invoice._compute_company_currency_amount(amount)
             tax_line = TaxLine()
             tax_line.amount = amount
             tax_line.type = 'base'
@@ -3537,9 +3544,7 @@ class InvoiceTax(sequence_ordered(), ModelSQL, ModelView):
         '''
         Return a list of move lines instances for invoice tax
         '''
-        Currency = Pool().get('currency.currency')
         pool = Pool()
-        Currency = pool.get('currency.currency')
         MoveLine = pool.get('account.move.line')
         TaxLine = pool.get('account.tax.line')
         line = MoveLine()
@@ -3547,11 +3552,8 @@ class InvoiceTax(sequence_ordered(), ModelSQL, ModelView):
             return []
         line.description = self.description
         if self.invoice.currency != self.invoice.company.currency:
-            with Transaction().set_context(date=self.invoice.currency_date):
-                amount = Currency.compute(self.invoice.currency, self.amount,
-                    self.invoice.company.currency)
-                base = Currency.compute(self.invoice.currency, self.base,
-                    self.invoice.company.currency)
+            amount = self.invoice._compute_company_currency_amount(self.amount)
+            base = self.invoice._compute_company_currency_amount(self.base)
             line.amount_second_currency = self.amount
             line.second_currency = self.invoice.currency
         else: