Wiring a Corner finder and height control

[D-man]

But shouldn't it rise 3 mm. To get the plate out and then drop 19 mm to Z 0 when goto zero is pressed or am I grasping this thing all wrong?

(16+3=19. Go to zero -19 in the positive direction)

And then for an example if an offset of say 5mm is set, then it would offset from Z zero 5mm

Is it possible that the plate is too thick for the settings/script? Reason i ask is when a clearance of 20mm is entered it then goes up. But then plunges too far