Damned if I know.
I have no idea what TTU’s and Houston’s recruiting rankings are, but I would guess it has something to do with that, home field advantage, and other things that just favor bigger schools
For instance, I glanced at the FSU-Samford probability the other day and it was 82% FSU win when Samford was up 9 or so in the 3rd. If that’s Colorado-Nebraska or something, I can’t imagine it would 82% in favor of the losing team, so it must factor in all the things certain teams have for it