I can't help but notice that when you meld stuff, there seems to be a hidden cap that once you reach over, you don't get stats for them anymore (For instance, a friend told me this ring can only be upgraded to have certain stats +4 control +4 craftsmanship and anything over would make the materia lose effect)

Can anyone chime in on this? Is there a list somewhere about all that? I have a feeling it is all based on ilvl...