diff --git a/NGCP/CDR/Exporter.pm b/NGCP/CDR/Exporter.pm
index 200f114..60d8e6f 100644
--- a/NGCP/CDR/Exporter.pm
+++ b/NGCP/CDR/Exporter.pm
@@ -228,7 +228,7 @@ sub prepare_config {
     }
 
     # backwards compat
-    $config{$stream . '.DESTDIR'} //= $config{$stream . '.CDRDIR'} // $config{$stream . '.EDRDIR'};
+    $config{$stream . '.DESTDIR'} //= ($config{$stream . '.CDRDIR'} // $config{$stream . '.EDRDIR'});
 
     if ($stream ne 'default') {
         # use constants from default, if missing:
@@ -491,7 +491,7 @@ sub apply_sclidui_rwrs {
             $row->[$i + $position_offset] = apply_rewrite(
                 number => $row->[$i + $position_offset],
                 dir => 'caller_out',
-                rwrs_id => prefval($reseller_id,'cdr_export_sclidui_rwrs_id') // 0,
+                rwrs_id => (prefval($reseller_id,'cdr_export_sclidui_rwrs_id') // 0),
             );
         }
     }
@@ -500,7 +500,7 @@ sub apply_sclidui_rwrs {
             $row->[$i + $position_offset] = apply_rewrite(
                 number => $row->[$i + $position_offset],
                 dir => 'callee_out',
-                rwrs_id => prefval($reseller_id,'cdr_export_sclidui_rwrs_id') // 0,
+                rwrs_id => (prefval($reseller_id,'cdr_export_sclidui_rwrs_id') // 0),
             );
         }
     }