This module allows to add comision en voucher.

models/account_voucher.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 from openerp import models, fields, api
-import math
 
 
 class AccountVoucher(models.Model):
@@ -22,7 +21,4 @@ class AccountVoucher(models.Model):
         porcentaje = float(param)
 
         for rec in self:
-            if rec.state == 'posted'
-                rec.comision = rec.amount * porcentaje / 100 if rec.amount else 0
-            else:
-                rec.comision = 0
+            rec.comision = rec.amount * porcentaje / 100 if rec.amount else 0