OP here, I actually never went back to try and find out which college made the adjustment, because it was so much in our favor that I did not want to stir up anything 
The college that first alerted us to the correction, which had already given us a FA offer prior to it, actually increased their offer after the correction (and after requesting our W-2s).
But now, new twist, last week there was another correction by another college. I think it’s finally time to dig deeper.