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)

""" Automatically create a journal entry to book the exchange rate difference.
            That new journal entry is made in the company `currency_exchange_journal_id` and one of its journal
            items is matched with the other lines to balance the full reconciliation.
        """
        for rec in self:
            if not rec.company_id.currency_exchange_journal_id:
                raise UserError(_("You should configure the 'Exchange Rate Journal' in the accounting settings, to manage automatically the booking of accounting entries related to differences between exchange rates."))
            if not self.company_id.income_currency_exchange_account_id.id:
                raise UserError(_("You should configure the 'Gain Exchange Rate Account' in the accounting settings, to manage automatically the booking of accounting entries related to differences between exchange rates."))
            if not self.company_id.expense_currency_exchange_account_id.id:
                raise UserError(_("You should configure the 'Loss Exchange Rate Account' in the accounting settings, to manage automatically the booking of accounting entries related to differences between exchange rates."))
            move_vals = {'journal_id': rec.company_id.currency_exchange_journal_id.id, 'rate_diff_partial_rec_id': rec.id}
            
            
            
            if move_date > rec.company_id.fiscalyear_lock_date:
                move_vals['date'] = move_date
            move = rec.env['account.move'].create(move_vals)
            amount_diff = rec.company_id.currency_id.round(amount_diff)
            diff_in_currency = currency.round(diff_in_currency)
            line_to_reconcile = rec.env['account.move.line'].with_context(check_move_validity=False).create({
                'name': _('Currency exchange rate difference'),