It seems that the reason Cinci is ranked ahead of BYU is money. Based on the records of both teams, each team deserves to be ranked in the top 8 to 10 at least. However, the CFP committee could not let 2 teams outside of the power conferences get a N6 game.
Why? Because of the big 5 conferences need the bowl revenue even though it will be divided into small pieces of 10 to 12. They threw Cinci the bone because they are in a conference and the state of Ohio is a bigger football market than the state of Utah.
It's not fair but that's the way college sports is these days. It's not about fairness its about money.