how come sometimes after waking up and checking if the icloud back up worked when your phone is locked on wifi and connected to the charger sometimes it says it backed up right after you plugged it in at first and other times if waits for maybe 6 or 7 hours to back up. one night i went to bed a 11 and it backed up at 1130 and the other night i went to bed at 11 and it didn't back up unitl 7am!? why is that? i feel like some nights it doesnt even back up and then when i put it back on the charger in the AM it then backs up? thoughts?