Just to share with those needed help on fixing I-94 date...
Last year my I-94 had a wrong date when I returned to US. I did not realize it till very late. I went to USCIS office (appoitment on infopass.com) and waited for 2 hours (even with appoitment) to talk to one officer and the superviser (both don't know much, but they scared me by saying I was out of legal status). I insisted on going to the Deferred Inspection site office and there it took only 15 minutes to have the wrong date fixed.