It is my understanding that most of the bile released when one is fasting is "old" stagnant bile. It is also my understanding that fat is a store house for toxins and that is the main reason one will lose some fat while fasting.
You actually pass "green stones" during the MC? If so this would be the first case I've heard of in all the time I have been around here.
The reasoning for waiting to do an LF after the MC till one is eating reagular and has started adding fats to their diet is so that the system will have started producing bile so one will have a more productive LF.
I would defienetly say that passing actual green stones during the MC is more of an anomaly than the norm. Whatever the reason or cause BOTI (better out than in) ;+D