I received an email at lunchtime today saying I have used 50% of my data for the month. I have the (only) 200MB plan.
Now I have a look after work and the Usage Meter tells me I have used 120MB.
My problem is that I run a little app called "DroidStats" that tells me I have used 80MB. 
When I looked at the usage meter for todays data and look at DroidStats for todays data, they match. Now why dont the monthlies match? How could they be out by 40?
Any ideas?