POSSIBILITY #1
If you pass lots of stones it means that your gallbladder is very healthy as the large amount of bile that it is capable of creating and squeezing out will form a lot of stones when the olive oil binds the bile into newly formed balls. If you did a dozen flushes and continued to pass Hundreds of stones each time it would suggest to me that this theory is correct as preformed stones would eventually run out. Since the stones continue to be passed they are probably being newly formed by the bile mixing with the olive.
POSSIBILITY #2
Passing a lot of stones means that your gallbladder was blocked up with stones prior to the flush and you managed to get them out. The extra stones passed with each new flush are those that moved forward into the bile ducts after the last flush. As previously stated the stones stored in the gallbladder and liver must eventually run out. If you did a dozen flushes and got less stones each time that might support this second of two possibilities.
Has any done a lot of repetitive flushes at one or two week intervals that can comment on their stone count at the beginning compared to the stone count recorded as more flushes were performed?