I am using iPhone 4, iOS 5.0, Currently on Maxis's Value Plus Internet 80.
And the weird thing is
I found out my data usage increase with Wifi on.
My room have wifi on 24/7, and I can still online when I woke up
Yesterday before I slept I check my GPRS Usage with *100# (short cut key is 6-1-7) and it showed
44.72mb as at 11:30 16-12-11
But I just woke up and check again
45.12Mb as of 5:35 17-12-11
increase 0.4Mb in 5 hours itself.
Today I am not going to use any 3G related apps /function, gonna see how much it used up again, cause I notice my usage increase quite a lot!
I got the same problem as you too..from the other thread, 1 of the member said that it is related to ICloud syncing while it is in standby mode...I guess we have to wait for Apple to update the new firmware to incorporate a 3G on/off setting...