I mean...even if that's how percentages worked...you be giving yourself a 25% of it being successful (assuming it was unsuccessful the first time, resulting in doing it again)
@Drunk Pantless Uncle, I could be wrong, but I think if you did it twice, there would be a 25% chance of it being successful twice. You would actually have a 75% chance of it being successful once out of the 2
This make me think of the McDonald's' Third Pounder disaster.