There are different views on this, I never did. I actually started out with the liverflush since I had gallbladder problems and later found out about the other cleanses. I did parasite once after 2 years, but because of the flushing I was already clean I assume.
You can do the bowelcleanse and add the liverflush with that. On the day of the flush you skip the bowelcleanse.