I'm beginning to wonder if the sudden overloading of the liver with oleic acid interferes so much with conversion to cholesterol esters that it actually causes "free" cholesterol to "clump together", producing sort of "instant stones". This would go along with some people saying their stones are "almost pure cholesterol", whereas "real" cholesterol Gallstones are not.
The dumping of excess cholesterol in this way would account for beneficial effects of the cleanse.