Does stat bonuses from materia degrade when you meld them into lower armor (earrings, rings, necklaces and the like) ?

I melded an Intelligence Materia III to a lv.50 earring and it came out with "Intelligence +1" in red writing.

A lv.50 goldsmith whisped me and said you won't get the full benefit of the materia if the item level of the armor is lower than the materia level. However, the item that the materia was melded to was a lv.50 earring with an item level of 55, while the materia is item level 45.

Can anyone provide some info, I'm rather confused