Honestly, my guess is the move had less to do with money (though, some to do with money, of course), and more to do with future hc aspirations. I've been impressed with KU's scheme since Lance and co. got there, but I don't really know who was the secret sauce. Lance? Andy? Hard to tell. Who is the brains behind that operation?
If Kotelnicki wanted to be a head coach, that's probably what dings him. Him being able to replicate that kind of impressive production somewhere (really anywhere) else without Lance gives him the chance to show ADs that he's smart on his own. That's one thing Klein, for instance, doesn't really have to wrestle with because Klieman doesn't have an offensive background (whereas Lance dicked around as an OC for no-name programs in the past). Doing it for probably $1.5m+ at a high profile spot is a chance for him to prove his merit to become a HC.