diff --git a/models/pos_config.py b/models/pos_config.py
index 1b579f0..451ae5c 100644
--- a/models/pos_config.py
+++ b/models/pos_config.py
@@ -8,5 +8,6 @@ class PosConfig(models.Model):
     @api.model
     def _load_pos_data_fields(self, config):
         fields_list = super()._load_pos_data_fields(config)
-        fields_list.append('reward_point_digits')
+        if fields_list:
+            fields_list.append('reward_point_digits')
         return fields_list