In their last 12 games, OU is 8-4 and MSU is 9-3. If you average the RPIs of the teams they have played in those 12 games, MSU's comes out to 100 (99.9) and OU's is 55 (55.0). I would say that is significantly different.
It comes down to conference tournaments. Winners will get a 1 seed (of the ones that are currently a 1 seed or a 2 seed).