Ann154 I'm trying that option out now. I went on and saw that i was charged data while home late this morning as well so i don't think it's the sleep setting anymore as i had used my phone earlier this morning. I have the "smart network switch" option turned off (has always been off) so it shouldn't ever switch between the two when i'm on WiFi in the first place according to the tech I was on the phone with. from the other things i've read this sounds like a fairly common complaint from other customers. i also have the setting set so that apps don't update unless connected to wifi...so i have no idea what could possibly be happening when i'm not using the phone in order to show data usage. Seems pretty convenient that i finally upgrade my phone and all of a sudden my data usage doubles with no changes to my usage habits.