Dennis Dodd says that after Bowlsby's comments that the Big 12 would always be at a disadvantage, that the CFP officials told him the 13th game was the difference, those officials stressed that it made a difference last year. They said that OSU's win (over a ranked opinion), especially the score, was the determining factor in vaulting OSU over Baylor. They, apparently never said it would be a determining factor every year.

Dodd also indicates that if/when CCG deregulation occurs, divisions may be a thing of the past. He includes an analysis of the frequency of upsets in conference championship games.
In 56 ACC,BIG,Big 12, Pac-12 and SEC CC games, the two highest ranked teams did not meet 66% of the time.

http://www.cbssports.com/collegefootball/writer/dennis-dodd/25173834/how-a-conference-title-game-could-affect-big-12-national-title-hopes