diff --git a/l10n_nl_xaf_auditfile_export/models/xaf_auditfile_export.py b/l10n_nl_xaf_auditfile_export/models/xaf_auditfile_export.py
index 242b18a6a..8b11c66d0 100644
--- a/l10n_nl_xaf_auditfile_export/models/xaf_auditfile_export.py
+++ b/l10n_nl_xaf_auditfile_export/models/xaf_auditfile_export.py
@@ -251,46 +251,21 @@ def get_taxes(self):
             ('company_id', '=', self.company_id.id),
         ])
 
-    @api.multi
-    def get_ob_sql_fragment(self):
-        """
-        return a from clause and a where clause selecting the
-        relevant lines for the opening balance
-        """
-        return self.env.cr.mogrify(
-            "from account_move_line l, account_account a, "
-            "     account_move m, account_account_type t "
-            "where a.user_type_id = t.id "
-            "and a.id = l.account_id and l.date < %s "
-            "and l.move_id = m.id and m.state = 'posted' "
-            "and l.company_id=%s "
-            "and t.include_initial_balance = true ",
-            (self.date_start, self.company_id.id),
-        ).decode('utf8')
-
     @api.multi
     def get_ob_totals(self):
         """return totals of opening balance"""
-        self.env.cr.execute(
-            # pylint: disable=sql-injection
-            "select sum(l.balance), count(distinct a.id) " +
-            self.get_ob_sql_fragment() +
-            "and l.balance < 0"
-        )
-        row = self.env.cr.fetchall()[0]
         result = dict(
-            credit=abs(round(row[0] or 0.0, 2)),
-            count=row[1] or 0,
-        )
-        self.env.cr.execute(
-            # pylint: disable=sql-injection
-            "select sum(l.balance), count(distinct a.id) " +
-            self.get_ob_sql_fragment() +
-            "and l.balance > 0"
+            credit=0.0,
+            debit=0.0,
+            count=0
         )
-        row = self.env.cr.fetchall()[0]
-        result['debit'] = round(row[0] or 0.0, 2)
-        result['count'] += row[1] or 0
+        for line in self.get_ob_lines():
+            balance = line['balance']
+            if balance > 0:
+                result['debit'] += balance
+            else:
+                result['credit'] -= balance
+            result['count'] += 1
         return result
 
     @api.multi
@@ -299,8 +274,15 @@ def get_ob_lines(self):
         self.env.cr.execute(
             # pylint: disable=sql-injection
             "select a.id, a.code, sum(l.balance) " +
-            self.get_ob_sql_fragment() +
+            "from account_move_line l, account_account a, "
+            "     account_move m, account_account_type t "
+            "where a.user_type_id = t.id "
+            "and a.id = l.account_id and l.date < %s "
+            "and l.move_id = m.id and m.state = 'posted' "
+            "and l.company_id=%s "
+            "and t.include_initial_balance = true "
             "group by a.id, a.code",
+            (self.date_start, self.company_id.id),
         )
         for result in self.env.cr.fetchall():
             yield dict(