Rear Trailer Camera

[Desmo]

I purchased the GM rear trailer camera kit (84876819) and I just have one question about the instructions. The instructions state that the mounting height for the camera on the back of the trailer should be the sum of the measurement form the ground to the center of the tailgate camera + 100mm(~3 15/16"). Should this measurement be taken with the tuck on flat ground with or without the trailer connected?

 

It may not even matter, but I am assuming that the measurement form the ground to the tailgate camera should be taken with the trailer is hitched up to account for the squat. The instructions also state the the target area for camera mounting is a 400mm x 400mm square, with the ideal position in the center, so the squat may not even matter that much. Thoughts?