I don't know how that works, but I do have semi-automatic tranny experience.

The CAT 7155 is a 16 speed semiautomatic tranny. It uses air-actuated shifter and clutch mechanisms. While the DEEEEEEP underdrive of the low gears would be awesome off road (4 mph top speed in 1st gear), the clutches would wear out quickly. The clutch determines how hard to apply itself based on the input from the crankshaft... 700 rps means no clutch, 1200 means engage quickly. If you are negotiating an obstacle, the clutch would not apply enough force to get up until about 1100 rpm, but you would then lurch forward, losing traction in the process.

I believe the unit you are talking about is more like an automatic tranny, with changes to the valve body... This would allow the unit to only engage the gear selected, until you input another gear. Same thing as running an auto in L1, but when you shift to L2, it will never go back into L1 without your input. Just like an auto, you would have to keep an eye on the fluid, as your input may require more slip from the torque convertor, and more shearing of the fluid.