Clarifying the epic potential scroll

Rare and below should merit that the scroll can be used on non potential'd items...if there is no confirmation on this I will check later as I am cubing when I get home tonight.

I used one on an item and it failed and boomed...guess I should've used a 20% first? lol

I'm curious as to where you got the logical breakdown of 16% fail no boom and 4% fail boom o.o...my assumption would be if failed, 80% chance no boom, 20% chance boom (I always assumed once a scroll that can blow an item up fails, it goes into a different section, almost like an "if then" statement or flowchart of sorts).

P(Success) = 80%
P(Fail) = 20%
P(Boom | Fail) = 20%

So if the scroll is used, it has a 20% chance to fail. If it fails, it has a 20% chance to boom.

So First of all, we only worry about the 20% chance to fail part. Now of that 20% chance of failing, 20% of that causes a boom. Therefore 20% of 20% is 4% boom, which means 16% of nothing happening