diff --git a/tariffs/tariff_naz.json b/tariffs/tariff_naz.json
index 926cdf9..5507c40 100644
--- a/tariffs/tariff_naz.json
+++ b/tariffs/tariff_naz.json
@@ -31,11 +31,15 @@
   ],
   "TimeBase": [
     {
+      "tbase_id": 0,
       "tbase_type": 0,
+      "tbase_type_comment": "time is given as starting from some wall-clock-time",
       "tbase_label": "absolute time"
     },
     {
+      "tbase_id": 1,
       "tbase_type": 1,
+      "tbase_type_comment": "time is given as starting from 0 minutes",
       "tbase_label": "relative time"
     }
   ],