The statistics on your phone have to be manually reset at the same time the provider's billing cycle flips over - good luck with that. And the stats on my wireless hotspot are always inaccurate. With AT&T they also say there is about a 3 hour delay with the usage statistics in their iOS app.
Honestly it's a minor annoyance. But I think it's funny that every month, it's the same right before my cycle ends.