Novus weapon upgrade system findings

[Giantbane]

Hello 75 Alexandrites and 15m gil in rank III and IV materias.....

Any idea when we start needing rank 3/4 materia? The quest makes it seem like higher materia are needed to break specific thresholds. IE. you'd only need a rank 3 for every 10, 20, 30th alexandrite ... or something like that.