I believe Peej averages 8.5 if 2020 is tossed out.
I believe you should double-check your math.
Tossing out 2020, PJ has won 55 games in 7 years (including bowl games). That translates to 7.85 wins per year. Not bad at all, but not 8.5.
It's worth noting when comparing PJ's wins per year, to Kill, Kill to Brewster, Brewster to Mason, and so on, there are 25% more bowl games today than when Mason coached.
Some perspective that conflates what PJ has done:
Murray Warmath likely would have coached in 7 more bowl games than the two Rose Bowls he did coach in.
Call Stoll would have coached in 4 bowl games instead of the 1 he did.
Joe Salem would have coached in one bowl game
Gutey would have coached in 5 bowl games vs. the 2 he did.
Waker would not have coached in a bowl game.
Mason would not have coached in any additional bowl games, but coached in 4 more than he would have if he coached before the Bowl explosion.
Brewster would not have reached a bowl
Jerry Kill would have coached in 1 bowl.
Claeys would have coached in 1 bowl
Fleck would have coached in 1 bowl