Apparently, having multiple possible offers can make you more likely to be a IPH. Every IPH is either someone who had no possible offers, or only had offerers who individually were the only possible match for another participant, so you get rolled out into the initial batch at the end.

I've been a pinch hit twice. Both times I got better than average fic, but that's probably because fandom friends claimed me both times. I've gotten plenty of better than average fic from the general pool, but those obviously have greater hit-or-miss odds.