CSU holds 32,500, but has more premium seating. We also don't know how much of a split Arkansas is getting of that. My sense is that TU would not budge while other teams might. Castiglione is on record as saying he didnt care about the split for the OU games in Tulsa because it wasn't about the money. It was about older Sooner fans in the Tulsa area getting to see the team because they can no longer make the long drive back after the games in Norman or some other sob story.
Athletic Directors are also aware of the quirky demands of major boosters and that can influence the decisions where road games are played. It can be simple or very complex. Hypothetical: Major Arky booster meets major booster from another school at some random game five years ago. They get drunk and share their love of skiing to each other. Arky booster promises major booster from Michigan or wherever that they will get together one day and go skiing before a game. Major booster hears from AD they need to add a road game, so Major booster tells him to book a school near a skiing destination so he can invite his buddy to go skiing in hopes an invitation to come up for the Ohio State Michigan is offered later. This happens A LOT. One of my clients here in Tallahassee is a booster for FSU that makes Mike Case's contributions to TU look like the widow's two mites. He has given millions in additional donations and purchased additional advertising to have a direct say on where FSU plays football, basketball, and baseball on the road for this purpose, even where the alumni association takes group overseas trips in the off season. (They wanted to go to a Muslim country where alcohol wasn't served. If they wanted my client to go, they had to change the destination so he could drink on the trip).
There is also a whole subculture of major boosters influencing other program's major boosters on what teams that program schedules so they can trade access to suites. He participates in that process. You've got that right. I know for a fact he has had at least one SEC conference game moved on the schedule, by using his booster contacts at that SEC school, to accommodate him. He wanted to come up and party and see game day at that school. He could only go on a particular weekend, because of scheduling conflicts with FSU. That SEC school had actually planned on scheduling an open date on that weekend to get ready for out of conference rival the following weekend. Prior to the SEC school's final schedule being released to the public, calls are made, and suddenly there is an SEC game to be played on that date. TV contracts are amended, lots of logistical issues created, just because one guy from FSU wanted to see a game up there and knew a booster at that school who wanted to come down and enjoy UF at FSU from a suite when both teams were ranked in the Top 5.
This is a long way of saying Tulsa shouldn't take it personal. There are so many random factors that go into OOC scheduling, you will never know why they would do a 1-1 with CSU. The real reason could be a lost poker bet 20 years ago or the athletic director has a second home up the road.