Probability on fusing and sockets is weird as fuck because it's not independent.

Like generally you can consider it independent, but technically using a jew or fuse will always result in a different result. It's easier to look at it from socketing. So if you have 1 socket if you use a jew you can't get 1 socket again so your probability is actually higher on that roll of hitting 6 sockets than if you had like 3 sockets. However once you reach low enough probabilities it doesn't really matter too much.

So it's likely the probability of each option is nice numbers, but because you can't get the exact same configuration each time the calculated chance turns out to be some weird number. Which technically also fluctuates based on how many links you started with.