As I understand it you need to take the GCG right up until the flush IF your stones from the last flush were big (about 1 inch). If they were small you may not need to continue the GCG at all. You can also take the GCG throughout, so for example, for three months straight until your next flush. This will keep crushing the stones. But if you take a month off, you generally need to start over. Especially with the apple juice, that's just temporaty I think, but I'm not sure. Also, if you wait for too long between flushes, the galbladder will have time to produce new stones and the small crushed up stones may be squished together and reform new big stones.
Lisa