I would assume on average that a P5 team would expect to place a team in the playoffs around 70-75% of the time. This allows for the occasional situation where 2 teams from the same conference end up getting in. In their current setup the Big 12 may only be expecting getting into the playoffs around 2 of 3 years (roughly 67%). By expanding to 12 teams and reducing the conference games by 1 it would increase their playoff likelihood to be comparable to that of the other P5 conference (in the 70-75% range). Having not seen the data I obviously can't speak for that being what the results would be. However, it wouldn't surprise me at all if that's what the numbers are indicating.