You can't count on everything a company tells you in a presentation. The RadioInfo calls can be used for that, and that is the only way I've been able to find that kind of information. The problem is there are so many variables. Is the device in Wi-Fi cover. Even if it is, is some poorly written application using direct. Is the plan staggered with 50MB free for mail and 1GB free for web and everything else at $10/MB.

In any case, if you want to know how much data has gone to/from the Blackberry over a period of time you read those values at the beginning and the end of the period. The difference is the data use over the period.

Blackberries are very chatty, the values will more often change than not.