wow nice calculation.

So is this saying that for ANY item you RE, it increase the chance of getting schematic?

No.

Every individual roll is 20%. No matter how many times you did it before, it's only 20% each roll.

You chance, OVER TIME, is increased as odds say eventually you will hit the schematic. However each individual roll is 20% regardless of anything that has every happened before it.

This the classic gambler fallacy.