The only time that should ever come into play is if one team’s key players is hurt a la Florida State’s QB last season. But I think the playoff committee could use it to keep the loser of the Big XII CCG out.
The thing is college football teams only mostly play 11 other FBS opponents in the regular season. That is actually not a lot of data points. Also, what criteria is used to determine the next “best” team? You almost certainly have to take into account wins and losses which ultimately means you are looking at the most deserving teams.
Is the CFP committee really going to select a 3-loss Bama team if it loses another one score game during the regular season? Certainly on talent alone you could argue that Alabama is a better team than anyone in the Big 12 or SMU or Miami. But even then 3 losses is just too much. However they could possibly use that logic for a 2-loss Big 10 or SEC team to get in over a 1-loss Big 12 team that did not win it’s CCG (ie, in this case meaning BYU).
Here is a scenario that concers me. Let’s say BYU wins out but loses by two TDs to a 2-loss Colorado. Under this scenario let’s also assume that Boise St goes undefeated. Boise’s only loss would be a 3-point loss at Oregon. In this scenario I could see Boise getting the 4th seed, Colorado might be an 8-10 seed and BYU could possibly be left out for 10-2 SEC team, 12-1 Miami team that loses in the CCG or 11-1 Notre Dame. Even though BYU went undefeated in the regular season, I could see the comittee stating “we just think XYZ team selected instead of BYU are better than a BYU team that had a weak conference schedule and then lost convincingly to a 2-loss Colorado team that lost to a mediocre Nebraska team.”
The issue here is that there is bias and perhaps extreme bias especially when it comes down to the final at-large selections. It’s also why a BCS selection system would be better than a committee.