[Sawrock]

That's a fair point to make as well. But then we have to ask ourselves, to what degree would it be noticeable? Obviously a difference of healing 1 HP wouldn't be, but anything above a certain threshold is going to be in a more subjective than objective territory.

For a ridiculous example, someone might say that if homunculi take 15% less healing, and you have ten broken fingers, then you're healing eight and a half fingers compared to a full ten. One person may think 15% is noticeable, and one may not. For a less extreme example, someone healing all of their bruise compared to having some small amount of bruise left may be hard to notice, but not impossible.

I just can't view it as metagaming when it could easily be viewed through the lens of being in-character, unless we want to add rules for how much health has to be healed in comparison for it to be noticeable, and then that's getting a bit ridiculous in itself; a mindset like that can cause rule bloat.