I ran into the same problem. Basically I got it as close as possible (mine was within 7 hours) and left it at that. I think I played around with it for a good 2 hours trying to figure it out (and that was after another 3 hours of going through my logbook and totaling all the different aircraft I flew through training and instructing). If they ask, I'll just tell them the truth, it didn't match but I tried my best to get it close.