Once you get beyond the TV games, RPIs don't matter nearly as much anymore. It's a lot more about reducing travel and looking to the future.
I gave Illinois St the worse opponent this year but the better return game. Also there's the Coach Mo factor with WIU/BU and I think they would rather play BU than ISU. That's all there really is to it.
For interest of full disclosure:
away teams, Illinois St is #17 in RPI and Bradley #22
home teams, WIU is #16, Oakland #24
So it's definitely reasonable. I guess we'll settle it this week on the court
I know you also put up Drake/Green Bay....Drake is #18 in home RPI and believe it or not, Green Bay at #21 in away RPI is the only midwest team from #8 to #22 not in the MVC. That's why I put a future WCC team with UNI.