If it works similar to what JCA does, and that's a big IF. Here's what happened to JCA's last home game that was on NFHS.
1) Like SR, JCA usually broadcasts on YouTube and it's very good with HS kids as announcers.
2) If a playoff game is to be on NFHS, because they own the streaming rights, the JCA crew does their normal broadcast, but broadcast directly to NFHS instead of YouTube.
3) You end up with a high quality stream on NFHS.
It's also true that most playoff games on NFHS are a higher quality than regular season games in general. I'm not sure why.
But, if a certain school typically has streaming and buffering problems, there is a much higher chance that their playoff game will also have some problems.