Quote Originally Posted by PessimiStick View Post
I'm 90% sure that DET does nothing for heals ON you, only for heals BY you, but it would be incredibly simple to test, just get as low DET as possible, get spam healed by a WHM, take the average, then equip DET and re-test.
I think I would have to agree with this.

One way to test this is to take a low level Conjurer and cast Cure on a level 1 target. Then cast Cure on a level 50. If Determination affects incoming healing, then the level 50 should have drastically more HP restored.