I was also wondering if this was some type of data accumulation that was just posted at the end of the day. The only problem is that my wifes phone shows transfers of 20 MB, 30 MB, even 70 MB one night. That is a ridiculous amount of data, especially since all she really does is check email and occasionally read some news or maybe download an app. For our current billing cycle, we are about half over and over 300 MB already.
One of the really frustrating things is that when i called AT&T customer service to help solve this mystery, they basically threw there hands up. We dont have any tools to help diagnose, we dont really know anything about the phones and how they are setup, basically nothing. The lady i talked to said her first guess was either stats being collected by apple or updates to the phone. I feel pretty confident that these aren't the case. Her next suggestion was the setup of the email accounts on the phone. My wife has 2 email accounts and then calendar and contacts setup. The phone has a general setting for either pushing or fetching data, and then an advanced section were you can set individual mail accounts to behave differently. The phone general setting was set to push, her gmail account was set to fetch, and her yahoo account was set to push. Mail contacts and calendar was set to fetch. So what i did was change everything to fetch manually. So, here is the last couple of days of data charge. You will notice that i made this change during the day on the 5th. Look at my data usage on the 3rd and 4th, over 3 MB and 8 MB. Since the change on the 5th, no weird data transfers during the early morning hours. There are a quite a few spread out over the day of the 5th, 6th, and 7th, but they are mostly a few hundred KB, give or take. Another odd thing, before the 5th, most days i had maybe 1 or 2 data transfers, but always this mysterious one around 1 or 2 am. Since i made the change on the 5th, i have a lot more data transfers during the day, they are much, much smaller in size compared to before the 5th, but the mysterious transfers at 1 or 2 am have disappeared. I know, I'm scratching my head also...
06/07 06:13 PM phone Internet/MEdia Net Sent 4KB
06/07 06:07 PM phone Internet/MEdia Net Sent 586KB
06/07 05:39 PM phone Internet/MEdia Net Sent 124KB
06/07 12:04 PM phone Internet/MEdia Net Sent 4KB
06/07 12:02 PM phone Internet/MEdia Net Sent 4KB
06/07 09:29 AM phone Internet/MEdia Net Sent 297KB
06/07 09:19 AM phone Internet/MEdia Net Sent 27KB
06/07 08:19 AM phone Internet/MEdia Net Sent 58KB
06/06 03:53 PM phone Internet/MEdia Net Sent 191KB
06/06 03:45 PM phone Internet/MEdia Net Sent 761KB
06/06 03:18 PM phone Internet/MEdia Net Sent 228KB
06/06 02:58 PM phone Internet/MEdia Net Sent 2256KB
06/06 02:03 PM phone Internet/MEdia Net Sent 47KB
06/06 12:53 PM phone Internet/MEdia Net Sent 893KB
06/06 12:52 PM phone Internet/MEdia Net Sent 26KB
06/06 12:43 PM phone Internet/MEdia Net Sent 956KB
06/06 12:28 PM phone Internet/MEdia Net Sent 552KB
06/06 12:23 PM phone Internet/MEdia Net Sent 1034KB
06/06 10:37 AM phone Internet/MEdia Net Sent 31KB
06/05 12:55 PM phone Internet/MEdia Net Sent 68KB
06/05 12:42 PM phone Internet/MEdia Net Sent 898KB
06/05 12:32 PM phone Internet/MEdia Net Sent 22KB
06/05 12:26 PM phone Internet/MEdia Net Sent 21KB
06/05 12:23 PM phone Internet/MEdia Net Sent 67KB
06/05 11:36 AM phone Internet/MEdia Net Sent 194KB
06/05 11:07 AM phone Internet/MEdia Net Sent 1728KB
06/05 10:51 AM phone Internet/MEdia Net Sent 221KB
06/05 10:43 AM phone Internet/MEdia Net Sent 1319KB
06/05 10:30 AM phone Internet/MEdia Net Sent 7KB
06/05 10:21 AM phone Internet/MEdia Net Sent 129KB
06/05 10:16 AM phone Internet/MEdia Net Sent 102KB
06/05 10:02 AM phone Internet/MEdia Net Sent 1003KB
06/05 09:32 AM phone Internet/MEdia Net Sent 2410KB
06/05 01:22 AM phone Internet/MEdia Net Sent 667KB
06/04 01:22 AM phone Internet/MEdia Net Sent 3368KB
06/03 01:45 AM phone Internet/MEdia Net Sent 18906KB