Wow a fair few questions. The quick answer is Yes of course it can.

When the bucket is on the floor and grading / digging the machines not rocking about so much, and the 2D sensor which measures pitch/roll & slew will compensate for uneven machine position.
Additional sensor £600 no problem with sharing between machines.
The machines with extending dippers can be calibrated with 2 profiles (dipper in & dipper out) bit of a compromise but once you get the hang of it it’s easy enough, and still very accurate.
During installation we try to spend as much time with the customer to show the installation and calibration process. The whole procedure can be done in an hour, and with a little know how the plates can be removed and re used on another machine.
Tilt sensors can be used for any tilty or tilt bucket. The system also integrates seamlessly with Engcon EPS (rotation position) other manufacturers coming soon.
I’d be interested to know what machines your interested in using it on.