Sadly, the number of second dive location for people on air is very limited.
Dive in a lot of places on the eastern seaboard, and both nitrox and a computer are required...if you did that, they would loose half their customers, but be able to dive anywhere the divers wanted...well, until they went out of business.
This is exactly what ends up dictating most of the dives on boats that carry out 16 or more "random" divers.
It is always a better dive plan when 6 existing advanced divers do a private charter, on Nitrox and with computers. However it isnt cost effective for the majority of divers.
For the customer base that Scubatech is dealing with, especially on the weekends, I believe they do a good job of balancing the diving.