Numbers may well be "just for discussion", but the numbers you've used as examples are insane
Common items = 1 common fragment (up to 6, if FF'd) - heck, ALL items should just extract to between 1 and 6 fragments of their own class..
The fragment costs are, if you noticed, a lot lower for each tier of rarity (even though, in the first draft, crystalline, Elite and SE items were forgotten)
My point is that for exemple you can use multiple types of itens during composing like
An potion will require 50000 fragments (again exemple ... )
using that recipe I last posted It will be like
10 SE itens + gold OR 20 cristaline itens + gold OR 50 legendary + gold
or even use 5 SE itens and 10 cristaline itens + more gold. Instead of using a predesigned recipe for a potion you get to choose what itens you'll use IF you can reach the required amount of fragments and the gold needed