diff --git a/addons/account/models/account_reconcile_model.py b/addons/account/models/account_reconcile_model.py
index 624767875a7..67de4ee148b 100644
--- a/addons/account/models/account_reconcile_model.py
+++ b/addons/account/models/account_reconcile_model.py
@@ -237,7 +237,11 @@ class AccountReconcileModel(models.Model):
 
         # Second write-off line.
         if self.has_second_line and self.second_account_id:
-            line_balance = balance - sum(aml['debit'] - aml['credit'] for aml in new_aml_dicts)
+            remaining_balance = balance - sum(aml['debit'] - aml['credit'] for aml in new_aml_dicts)
+            if self.second_amount_type == 'percentage':
+                line_balance = remaining_balance * (self.second_amount / 100.0)
+            else:
+                line_balance = self.second_amount * (1 if remaining_balance > 0.0 else -1)
             second_writeoff_line = {
                 'name': self.second_label or st_line.name,
                 'account_id': self.second_account_id.id,