Yes, that is correct. But it is not only for TATA I feel. When we use a volume based plan, time based plan it is very difficult to track the usage and the providers are having a good chance to cheat people. Even with Airtel Mobile Office i was facing the issue. I have billed 1000 etc apart from my normal billing. But when i converted my connection as corporate, the billing became very fair and it was very less. Moreover i guess the application provided by TATA shows the downloaded data and not the uploaded data volume. Please check and let me know if it is wrong. I am not worried of the billing as i am into Unlimited plan with Tata and i disconnected my Airtel mobile Office GPRS connection.