diff --git a/bin/addons/base/res/res_currency.py b/bin/addons/base/res/res_currency.py
index d4a82c6b9a5..3c59527d5f9 100644
--- a/bin/addons/base/res/res_currency.py
+++ b/bin/addons/base/res/res_currency.py
@@ -67,14 +67,17 @@ class res_currency(osv.osv):
 	def round(self, cr, uid, currency, amount):
 		return round(amount / currency.rounding) * currency.rounding
 
-	def compute(self, cr, uid, from_currency_id, to_currency_id, from_amount):
+	def compute(self, cr, uid, from_currency_id, to_currency_id, from_amount, round=True):
 		if to_currency_id==from_currency_id:
 			return from_amount
-		[from_currency]=self.read(cr, uid, [from_currency_id])
-		[to_currency] = self.read(cr, uid, [to_currency_id])
+		from_currency=self.browse(cr, uid, [from_currency_id])[0]
+		to_currency = self.browse(cr, uid, [to_currency_id])[0]
 		if from_currency['rate'] == 0 or to_currency['rate'] == 0:
 			raise osv.except_osv('Error', 'No rate found for the currency')
-		return self.round(cr, uid, to_currency, from_amount * from_currency['rate']/to_currency['rate'])
+		if round:
+			return self.round(cr, uid, to_currency, from_amount * from_currency.rate/to_currency.rate)
+		else:
+			return (from_amount * from_currency.rate/to_currency.rate)
 res_currency()
 
 class res_currency_rate(osv.osv):