I think this is math vs human perception. We know all to well the perception of a team that wins by couple of points by scoring in the last seconds. The whole post game is about how this team is a winner, their players are amazing, their future is bright, etc. and the losers are the opposite; whereas in reality, it is a statistical tie. This dichotomy is so pronounced that I find it very amusing watching games when I don't have any rooting interest.
But for the computer, not only is it a statistical tie, but the loser may have, in quantifiable terms, played better than the winner. But in the human poll, they lose 10 spots and the winner gains 5 spots, and the division is magnified beyond reality.
All S&P is saying is that given a Baylor or Tulsa or KSU or God forbid, Maryland, we are a one score toss-up, or in other words, a statistical tie. Also, given an ISU, OSU or TTech, we are predicted to be, surprise-surprise, a toss-up. The difference of some toss-ups being above us is secondary effects.