I grossly misread the rules for this thing.

Instead of giving you a hit die's worth of hit points, it gives you one hit point per hit die (class level, for us) you already have. Then it gives you +1 hit points at each new level. This works out to a bonus of 20 hit points at level 20, regardless of when you took the feat.

Since I cocked up, I'm not (yet) making anyone change it, because if we do revert to how it's supposed to be used, you will probably want to look at other feats that are more worthwhile.

However, if there's something else you'd like that seems more appropriate, you're perfectly welcome to swap feats at this point. If you want to voluntarily scale the hit points back and use the feat as it's supposed to, then that's fine, but it may unbalance your character if no one else is as honorable as you.

I may wind up mandating that we do have to retroactively change, but I'd like to hear what you think first.