Each game in Sagarin is evaluated as "zero sum". The winner usually takes points from the winner. Because the system is figured from scratch every week and evaluated until the ratings "converge" and you can lose or gain points if teams you have already played lost or gained points, Ohio's and CMU's rating won't sum to exactly the same number this week as last. But you would find that the change of the combined ratings of teams that play each other in a given week should average out to zero.

The P5 conferences are well above .500 in their collective winning percentage. You might think that playing .500 against each other in conference would drop their rating. That won't happen. Conference rating will be almost entirely determined from OOC games. They will exchange ratings points within the conference playing each other.