diff --git a/account_spread_cost_revenue/models/account_spread.py b/account_spread_cost_revenue/models/account_spread.py
index 48b4f2f1..ad7484e5 100644
--- a/account_spread_cost_revenue/models/account_spread.py
+++ b/account_spread_cost_revenue/models/account_spread.py
@@ -1,4 +1,4 @@
-# Copyright 2018 Onestein (<https://www.onestein.eu>)
+# Copyright 2018-2019 Onestein (<https://www.onestein.eu>)
 # License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
 
 import calendar
@@ -382,9 +382,6 @@ class AccountSpread(models.Model):
         In case checks pass, invoke "def _compute_spread_board()" method.
         """
         for spread in self:
-            if spread.total_amount < 0.0:
-                raise UserError(
-                    _("Cannot spread negative amounts of invoice lines"))
             if spread.total_amount:
                 spread._compute_spread_board()
 
@@ -466,16 +463,28 @@ class AccountSpread(models.Model):
         spread_mls = self.line_ids.mapped('move_id.line_ids')
         if created_moves:
             spread_mls |= created_moves.mapped('line_ids')
-        if self.invoice_type in ('in_invoice', 'out_refund'):
+
+        spread_sign = True if self.total_amount >= 0.0 else False
+        in_invoice_or_out_refund = ('in_invoice', 'out_refund')
+
+        if self.invoice_type in in_invoice_or_out_refund and spread_sign:
             spread_mls = spread_mls.filtered(lambda x: x.credit != 0.)
-        else:
+        elif self.invoice_type in in_invoice_or_out_refund:
             spread_mls = spread_mls.filtered(lambda x: x.debit != 0.)
+        elif spread_sign:
+            spread_mls = spread_mls.filtered(lambda x: x.debit != 0.)
+        else:
+            spread_mls = spread_mls.filtered(lambda x: x.credit != 0.)
 
         invoice_mls = self.invoice_id.move_id.mapped('line_ids')
-        if self.invoice_id.type in ('in_invoice', 'out_refund'):
+        if self.invoice_id.type in in_invoice_or_out_refund and spread_sign:
             invoice_mls = invoice_mls.filtered(lambda x: x.debit != 0.)
-        else:
+        elif self.invoice_id.type in in_invoice_or_out_refund:
             invoice_mls = invoice_mls.filtered(lambda x: x.credit != 0.)
+        elif spread_sign:
+            invoice_mls = invoice_mls.filtered(lambda x: x.credit != 0.)
+        else:
+            invoice_mls = invoice_mls.filtered(lambda x: x.debit != 0.)
 
         to_be_reconciled = self.env['account.move.line']
         if len(invoice_mls) > 1:
diff --git a/account_spread_cost_revenue/models/account_spread_line.py b/account_spread_cost_revenue/models/account_spread_line.py
index 5c6c6bee..5e683c51 100644
--- a/account_spread_cost_revenue/models/account_spread_line.py
+++ b/account_spread_cost_revenue/models/account_spread_line.py
@@ -1,4 +1,4 @@
-# Copyright 2016-2018 Onestein (<https://www.onestein.eu>)
+# Copyright 2016-2019 Onestein (<https://www.onestein.eu>)
 # License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
 
 from odoo import _, api, fields, models
@@ -84,8 +84,8 @@ class AccountInvoiceSpreadLine(models.Model):
         line_ids = [(0, 0, {
             'name': spread.name.split('\n')[0][:64],
             'account_id': spread.debit_account_id.id,
-            'debit': amount,
-            'credit': 0.0,
+            'debit': amount if amount > 0.0 else 0.0,
+            'credit': -amount if amount < 0.0 else 0.0,
             'analytic_account_id': analytic.id,
             'analytic_tag_ids': analytic_tags,
             'currency_id': not_same_curr and current_currency.id or False,
@@ -93,8 +93,8 @@ class AccountInvoiceSpreadLine(models.Model):
         }), (0, 0, {
             'name': spread.name.split('\n')[0][:64],
             'account_id': spread.credit_account_id.id,
-            'credit': amount,
-            'debit': 0.0,
+            'credit': amount if amount > 0.0 else 0.0,
+            'debit': -amount if amount < 0.0 else 0.0,
             'analytic_account_id': analytic.id,
             'analytic_tag_ids': analytic_tags,
             'currency_id': not_same_curr and current_currency.id or False,
diff --git a/account_spread_cost_revenue/tests/test_compute_spread_board.py b/account_spread_cost_revenue/tests/test_compute_spread_board.py
index f9dec983..3465117d 100644
--- a/account_spread_cost_revenue/tests/test_compute_spread_board.py
+++ b/account_spread_cost_revenue/tests/test_compute_spread_board.py
@@ -1,4 +1,4 @@
-# Copyright 2017-2018 Onestein (<https://www.onestein.eu>)
+# Copyright 2017-2019 Onestein (<https://www.onestein.eu>)
 # License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
 
 import datetime
@@ -501,11 +501,10 @@ class TestComputeSpreadBoard(common.TransactionCase):
             'period_type': 'month',
             'spread_date': datetime.date(2017, 1, 7)
         })
-        with self.assertRaises(UserError):
-            self.spread.compute_spread_board()
+        self.spread.compute_spread_board()
 
         spread_lines = self.spread.line_ids
-        self.assertFalse(spread_lines)
+        self.assertTrue(spread_lines)
 
     def test_15_compute_spread_board_line_account_deprecated(self):
         self.spread.debit_account_id.deprecated = True