Ok I see what u mean. It is slightly different than the Buddha's explanation. He likened bad karma as a lump of salt in a river and the water surrounding it as good karma. If your river is tiny, the water is salty and life isn't sweet. But if your water flow is a big raging river, you won't notice the saltiness and life is good. The logic is not one of probability but of one force overcrowding the other and rendering it statistically irrelevant.