http://en.wikipedia.org/wiki/College_Football_Playoff#Revenue

Conferences will receive an additional $6 million each year for each team it places in the semifinals and $4 million for a team in one of the three at-large bowls; Notre Dame receives the same amount in either scenario. No additional money will be awarded for reaching the championship game.

Note that above this quote in the Revenue section it provides some details about how most of the money from TV rights have default disbursements to P5 conferences, ND, Go5 conferences and other independents. Those amounts will apparently not change based on number of teams that participate in any of the NY6 or semi-final games. The only increases each year will be based on number of teams in the semi-final games ($6M per team paid to their conference) and NY6 non-semi-final games ($4M per team paid to their conference).

There is some aspects of how some of the TV revenue is split for the contract bowls (Rose, Sugar & Orange) in years that they are not semi-final games that are different but in the end those differences will be standard regardless of how many teams from a conference make it into one of those games in a given year and only the $4-6M aspect will fluctuate per conf team that participates and in which type.....

I'm not sure where you got your $23.5M but perhaps that is what that may average out to considering set TV revenue +$4M or something like that....