Can you share your usage? I am trying also to run a PiAware feeding to both FlightAware and Flightradar24 and I am at 910MB from 1GB plan on that specific phone. In 7 days with heavier traffic I have racked 560MB of data (provider reports in increments of 20MB). This is without MLAT (on neither of the feeders) and with only an average of 28k positions daily (my home site gets around 385k daily).
I will check the phone on Monday too, but when I have checked last time, the phone logs reported similar data usage.
