I thought there were only two rules the NCAA has ever formally committed to:
1. If the host makes the tourney they must play in their regional.
2. 1-seeds are placed by starting at the #1 PWR, putting them in the closest site, then doing the same for 2 with the remaining sites, etc.
All other "rules," though they have been reverse-engineered so closely Jason Moy has picked the field exactly something like 7 times in a row, are still unofficial, even the one about not having intra-conference first round match-ups (which has never been violated and which I expect never will be).
At some point the selection committee made a statement that banding the 5-8 and 9-12 was at their discretion, combined with some mumbling about the band "edges" being basically within the noise anyway. Granted that was a while ago (my memory says 5 years which probably means 10), and they may have had formal statements to the contrary since then.
tl;dr: Whatever Ralph says I'm going with.