collective raise and lower cause ascent and descent at different rates depending on input device type and input type. Shouldn't these all be the same?

In the ah6/mh6
all figures in feet per minute from onboard VSI

keyboard:
2000 up
1800 down

mapped to joystick buttons:
7000 up and down

If you map the ANALOG collective to buttons on the joystick you get still another set of figures

2200 up
1800 down

however if using the analog collective inputs for non analog buttons, after releasing either button the helicopter falls at a rate of 1200 feet per minute until a non analog collective input is pressed.

In the KA-60
all figures in meters per minute from VSI on board

keyboard
600 up
600 down

joystick digital
2.5 up
2.5 down

joystick analog (mapped to a button)
700 up
600 down

  with a button release fall rate of 500 meters per minute

Please correct this issue

#2015