I've been thinking a bit more about this (always a dangerous sign :lol: ) - I'm not sure which is more concerning in this:
1. That your WLAN usage data is somehow being obtained by the phone network in the first place (without your expressed, freely given consent) or
2. If the phone is adding it to the statistics for the cellular data, why are the network using the handset's count to bill against - they ought to be metering their end of the connection not yours - apart from nothing else, it's much easier because they don't need to know what sort of instrument is at your end.