I'm throwing this idea out as sideways thinking logic of what could be achieved without a great deal of complexity.
I am using software called TurboCNC by DAK Engineering to control a converted manual metal lathe for both turning and light 3D milling. This software is capable of controlling eight axes as well as 40 lines for I/O from a printer port or two.
I think this software could be used to build a CNC controlled flow bench that would allow the user to do fully automated flow testing.
Just think about it for a moment, with an automated valve opener set up on each valve, automated flow reversing valves in the bench, and speed control for the blowers, you could flow test both intake and exhaust flows for each cylinder at the push of a button under computer control. All of this could easily be accomplished without needing to carefully adjust the valve opener knob, or read the dial gauge. The possibilities would only be limited by ones imagination.