Yeah, it's super weird. All three version of KO punch hit on frame 9 with the exact same damage (35% base, I dunno if KO punch is affected by staleness or not since it's a weird move) and knockback. Default has an extra hitbox on bone 16 with the same size and other parameters as the bone 0 hitbox all three share. It is possible but not necessarily the case that default might hit a bigger area (it depends on whether bone 16 and bone 0 on Mac overlap or not, and without having access to Little Mac's bone structure, that's impossible to know); none of my gameplay has ever implied that it does, but it is a strange difference in the code. The super armor difference is very real though; KO punch is armored starting f4 for both custom versions and f8 for default. I was very surprised custom verison even affected KO punch, but this is a pretty compelling reason in my book to bring neutral-2 on Mac since 4 more frames of armor is honestly a big deal.
