I don't believe you have to get any stones out in order to benefit from a liver flush.
Flushing out bile from your system can be beneficial even if you see no hard objects comeing out.
People on this forum are so much focused on getting stones out, or on reachng the point when there are no stones comeing out, they forget that flush in itself is the important thing, not stones. Not everyone has stones inside liver or gallbladder.
People who keep producing stones overnight may never reach the point of no stones flush. People are different. Do not get trapped into believing that your experiece has to be identical to experince of other posters.
Dont forget diet and excercise! What you do between flushes can be as important or more important than the Liver Flush itself.
Eating foods rich in good, natural, unprocessed fats can help your liver even more than one night flush.