still drop. BYU is only 5 votes behind. If a voter had BYU at 13 and Notre Dame at 10 with Clemson, Iowa State, and Texas A&M in between, BYU moves up to 11 and gains two votes on Notre Dame. Notre Dame didn't drop, but BYU still made up ground. Do that with even two voters and BYU moves ahead.

Yes the same could be true of Notre Dame, but Notre Dame is most concentrated at 8 and 9, while BYU is most concentrated at 10 and 11 on individual ballots. In between them is likely one of the teams that lost, so if BYU moves up one spot (more than Notre Dame) for each of those voters, BYU will jump ahead.