From my experience in my location, these box 12 numbers would be the same on all copies filed for Federal, State, City, or Local, but without knowledge of your location, I cannot explain the variation. I would first have her ask her employer the reason why these numbers differ. Her HR or Accounting Dept should be able to explain the discrepancy. It could be an error that needs correction, or it could relate to differing tax laws in various taxing jurisdictions. I do not have enough information to investigate further.
