Example:
Rankings finish like this:
8 Oregon
9 Cincinnati
10 Oklahoma State
11 Florida
12 BYU
13 Miami
BYU would get the last at large because they were #12, Cinci gets the Auto-Bid being the highest ranked conference champ.

Rankings finish like this:
8 Oregon
9 Oklahoma State
10 Florida
11 BYU
12 Miami
13 Cincinnati
Now BYU would get the last at large still because they were #11, Cinci gets the Auto-Bid being the highest ranked conference champ.
People think this means if Cinci finishes ahead of BYU we have more leeway because we can finish #12 instead of #11, when in reality we are still fighting with Florida and Miami in both scenarios for the last few at large spots. What Cincinnati finished at had NO impact on us getting our at large bid despite the needed ranking changing.