Wait wait...
you infuse a Savage Might III Materia which has a +4 on DET and it ends up as a +1 DET on the Scroll!?
So you really have to infuse 75 Piece of Materia and use the Grade II / III / IV just when you are able and have a better chance of infusion, and not because of the better Points?
I guessed a - for example SM III gives you +4 DET so it counts +4 on this 0/75 counter?
So in other words, you really sink 75 + Fails (supposed about 100) Alexandrite and Tons of Gil (Materia Buying) or Time (Crafing + Binding)