Sphere Scroll question (Animus Relic to Novus Relic)

Ive hit what I feel is a bit of a snag, I have several Piety Materia that range from Grade I to IV, and the Sphere Scroll is only letting me infuse the Piety I Materia, why? It keeps telling me "Materia of a different grade is required to enhance this attribute." like I said I have 4 different grades, but I cant infuse them and I had the necessary Alexandrite to.

you have first to infuse materia I when it caps, you infuse materia II then when it caps goes to materia III and then after that when it caps you can do materia IV

Oooouf, I had a feeling about that, thanks :3