Using 1 GB per day when all devices are off (airplane mode) and only using during free zone. I even pay $140 per month to get the extra bandwidth. This is outrageous. When are you going to provide customers with an hourly report of usage so we can document what is really going on?
Keep in mind that airplane mode just means your devices can't transmit. They can still receive data and that counts against your allotment.
There are a variety of 3rd party software application that can track your data usage. Supposedly Exede is going to provide a better data tracker, but I haven't seen it yet. I use Satellite Restriction Tracker and it can be setup to track data usage on an hourly basis.