https://www.reddit.com/r/ffxiv/wiki/enmity

I'll at least clear things up, as maybe I may have interpreted it wrong, and can also apologize for the words, including the insults (which also wasn't necessary to add into it).

Enmity is calculated on the total heal rather than the amount actually healed.

So a 500 heal that only heals 300 health would give you 500x0.5 = 250 enmity rather than something like 300x0.5+200x0.75=300 or simply 300x0.5=150.
This is correct. Enmity is calculated for the full value of any magic-based healing produced (attack power based healing such as Bloodbath has some special rules on a case-by-case basis).