Ergh, that process only means that you dont go ahead and break the items one after the other, but ensures that because they are all moving up at the same time that you can walk away with something. ( Ex. +4 x6-> +5x4->+6x2 , then one of the +6 breaks, at least you have one +6 left. )
The chance stays the same though, but this just ensures that even if you have bad luck, you will at least keep the highest remaining + because your not taking all of them from +0 to +10 or whatever. I think I failed at explaining this.