Configuration:
- Company Currency: MXN
- Tax 16%.
- Multicurrency, MXN and USD.
- Decimal precision: 4
- Currency Data:
MXN: rate 1.0
USD rates

| Database time | rate | Local time (Mexico) | 
| --- | --- | --- |
| 2016-09-09 00:00:01 | 0.054440 | 2016-09-08 17:00:01 |
| 2016-10-11 00:00:01 | 0.051815 | 2016-10-10 17:00:01 |

Steps to reproduce:

1. Create an invoice for 600 USD  + tax (16%) with date 09/09/16 (September 9, 2016) and when you validate in the journal entry is $12,784.7172 MXN.
3. Create a bank statement in MXN and add a line with date 11/10/16 (October 11, 2016) and amount $13,372.80 MXN.
4. When reconcile select the invoice and there is a difference ($588.0828 MXN) add a line with the difference and select an account for the difference. 
<img width="607" alt="captura de pantalla 2016-11-04 a la s 17 23 26" src="https://cloud.githubusercontent.com/assets/6758279/20025385/749605a2-a2b3-11e6-8b1a-4e9fbf1521ed.png">

**Note that the amount of difference is $588.08 in when you select the account**

5. Click on reconcile.

Expected behavior:
- Reconcile the invoice and create account move.

Current behavior:
- Raise an error  `Wrong credit or debit value in accounting entry !`

![captura de pantalla 2016-11-01 a la s 19 18 52](https://cloud.githubusercontent.com/assets/6758279/19913537/1c272866-a069-11e6-9b06-5851681c7fa5.png)

if not all_aml_share_same_currency:
                writeoff_vals['amount_currency'] = False
            writeoff_to_reconcile = remaining_moves._create_writeoff(writeoff_vals)
            
            remaining_moves = (remaining_moves + writeoff_to_reconcile).auto_reconcile_lines()
            return writeoff_to_reconcile
        return True
    def _create_writeoff(self, vals):
        """ Create a writeoff move for the account.move.lines in self. If debit/credit is not specified in vals,
            the writeoff amount will be computed as the sum of amount_residual of the given recordset.
            :param vals: dict containing values suitable fot account_move_line.create(). The data in vals will
                be processed to create bot writeoff acount.move.line and their enclosing account.move.
        """
        
        if 'account_id' not in vals or 'journal_id' not in vals:
            raise UserError(_("It is mandatory to specify an account and a journal to create a write-off."))
        if ('debit' in vals) ^ ('credit' in vals):
            raise UserError(_("Either pass both debit and credit or none."))
        if 'date' not in vals:
            vals['date'] = self._context.get('date_p') or time.strftime('%Y-%m-%d')
        if 'name' not in vals:
            vals['name'] = self._context.get('comment') or _('Write-Off')
        if 'analytic_account_id' not in vals:
            vals['analytic_account_id'] = self.env.context.get('analytic_id', False)
        
        if 'credit' not in vals and 'debit' not in vals:
            amount = sum([r.amount_residual for r in self])
            vals['credit'] = amount > 0 and amount or 0.0
            vals['debit'] = amount < 0 and abs(amount) or 0.0
        vals['partner_id'] = self.env['res.partner']._find_accounting_partner(self[0].partner_id).id