I think your approval should be very near. I once read on an attorney's website (don't remember now the URL) that since FP is valid for 15 months, INS adjudicates cases with FP done between 12 and 14 months ago as expedite cases. Since "normally" such cases are not so many in number, it's difficult to notice approval trend and confirm whether the above is true or not though.
Best wishes,
Jigesh