Reliance 3G prepaid data usage issues

A couple of queries, guys:

Is there a way of tracking data usage real-time on Reliance? It appears to be updated only once-a-day or something like that (both USSD and MBAL sms)!

Also,

It appears that Reliance consistently bills about 10% higher than my estimated data usage! Could it somehow be their way of recovering service tax from the prepaid data balance?

Thanks.

Dial---> *367*3# for 3g balance.it will not show how much u have downloaded but,only the balance and expiry date.*367# for main balance