The only real moving I could see is if a small college town just couldn't host in that short of time, but I think all P4+ND teams should easily be able to. It could be if like Appalachian State was on the cusp of hosting. Teams would rebel if they were clearly the 5 seed and had to play the 6 seed, which probably would only marginally improve tv ratings.
Usually what happens is this:
-Auburn and Alabama play last game of the season, Bama wins but then loses SEC Chanpionship game, gets #6 seed.
-Auburn is like 9-3 and slotted for the #11 seed, would be a rematch with Bama. They move them down to #12 to avoid the rematch.
What occasionally happens:
-Small school gets bumped from hosting for logistical or political reasons.
-Rather than make Oklahoma State (#10) fly to Oregon (#7) they have them play at Oklahoma instead when OU is the #6 seed.
What virtually never happens:
-Team that should be in gets left out
-Team well above the cut line (#8/9) that should host gets bumped down the pecking order multiple spots
They want to give themselves wiggle room though for situations like if the SEC gets 5 teams in.