I have found out the hard way that smart limits does not work for iphone data although the att sales people told us it would. After calling ATT about this issue and explaining that we were mislead by the sales people about the smart limits working for the iphone data usage the only answer I got was I had 30 days to return the phone and I could pay for more data. So now IM stuck paying for a phone with a feature I was LIED to about from an ATT sales person.