There are 2 different pan/tilt invert options:
1 - Setup > tab "dmx addressing" > window "dmx address setting"
Used for instance to move the beams, from left to right, of 2 face to face mirror lights.
2 - Setup > tab "fixtures settings" > section "3DView"
With some manufacturers, dmx value 0 to 255 moves the mirror from left to right, and with some other manufacturers, dmx value 0 to 255 moves the mirror from right to left. This parameter allows to match the movement in 3DView with all manufacturers.