Berman looked at season two and chose to sacrifice the supporting/recurring characters they had enjoyed up to that point (Seska and Culla.) rationalizing upsidedownly that what the fans really wanted was more space ships and explosions rather than storytelling and acting.
Lets just figure this out.
Removing the cost of a few recurring actors (6 episode contracts, mean that these tourists guys get paid almost as much as Wang per episode.) which would sum up to an extra 20 maybe 30 seconds of cgi-modelling.