I think in the past, the difference between 4 and 5,6,7 has been pretty slight, arguably at times reversed, so yes, I expect 4 to get upset nearly half the time, and 3 to get upset perhaps a third of the time. And upsets happen even when seeding is correct. And this adds one more tough game the eventual NC team has to win even if they are top four. I doubt bottom 8 wins it very often, maybe once a decade or so.