So, I just got in touch with an Agent. It seems that the Moogle Earrings Code convertion is not possible anymore, it's suspended, even though the codes still work.
So, the Moogle Earrings are now a Japanese exclusive in-game item.

Thank you Yoshi-P and your fake speech of "No Region-Exclusive in-game items and collectibles."

Niiiiice.... -______________-