BYU was #106. Through no fault of its own, BYU played the softest schedule she nice the days of the WAC.
Iowa State beat:
TCU (on the road)
OU #6 in the CFP final ranking
Texas #20 (on the road)
Florida #7 in the Cotton Bowl
It lost to
OK State #21
OU #6 in the conference championship
Their body of work does have one really bad loss but it also has four wins against 6 CFP final-ranked opponents (OU x2).