When talking about how many wins a team ends with you need to factor out the BYU game.

If BYU plays an 8-3 team and wins, they are now 8-4 and don't belong in your 'upper' tier of P5 teams
If BYU plays that same 8-3 team and loses, they magically now do.

Its rare for BYU to beat 9 win teams because for a long time that means that team could only lose 1 more game before not being considered in your 'upper tier'.

A 9-3 team that beat BYU is the same team as an 8-4 team that lost to BYU. You should change your numbers to reflect that. For example, both USC and Tennessee last year would have finished 9-4 if they beat us. It would have been 2 points against BYU, but instead because we won they weren't included.

Regardless, BYU's struggled against good P5/G5 teams. Most teams do. That being said, if we really want the 'P5' label or to be in a P5 conference we have to play these games. We have to get our program over the hump to the point where we can win these games.