Potential System, halp

Can someone confirm that 2/3 potential slots are random and not permanent upon each miracle cube reset? I mean is it like rank (stays at current or +1, i.e. rare -> epic -> unique), where you have a chance to get it to 3 slots if it was 2 before cubing and stays 3 forever? Or does each identification give you either 2 or 3 slots each time. I really want to know if it's still good to get pre-existing equipment ready, thanks.

I dont understand what you mean by slots.

> Something +6% and something-else + 3%
> 2 "slots"

EDIT: I read that someone (here on SP) got an improvement from +2bonuses to +3 through re-magnifying, not sure if legit though.