You're absolutely right .. it's different for everyone.
But on a personal note, don't give up on liver flushes! I had the exact same experience as you, five Liver Flushes and not much coming out on the last three. I thought maybe I was "done" ... and I took a long time off (maybe a month and a half) because my kidney was in such horrible shape after quitting coffee, I was afraid to flush.
I finally did my sixth two days ago, and a tremendous amount of stones (big ones too) came out! I guess my liver was just resting!