the past is going to push BYU back. BYU has had 2 great seasons in a row, and the three prior to that were mediocre, mediocre, poor.
I would guess that some of these formulas weigh team's performance over a longer stretch than just the one year prior. May seem silly you think to still give weight to a team's performance from a few seasons ago, but its their formulas and they probably have some good success with their formulas.