That is interesting and strange, I have never heard that they can't see stones because of sludge.
Besides I would have thought that some of the stuff you have gotten out so far was from the gallbladder too.
I have one gallstone 27 mm and it has been there for the 2 and half years I have been flushing. They never mentioned all the green "peas" I have gotten out so far.
The stone never shrank either even with taking softening supplements.