One would think the higher SMU is ranked the better the seeding for BYU. That said, I wouldn't hang my hat on such logical and unbiased thinking. There are too many other things that can influence the committee besides objectivity. As
@Thiefery reminds me quite often, BRANDS still matter.
The committee isn't dummies. They'll set up the rankings each week in order for them to utilize Skinner's Constant aka Flannagen's Finagling Factor. "
That quantity which, when multiplied by, divided into, added to, or subtracted from the answer you got, gives you the answer you should have gotten."
The committee screwed up and didn't use Skinner/Flannagen when they allowed Cincy and TCU into the CFP. Those teams got blown out. (Well, TCU did beat Michigan but the next game was a total disaster.)