raymo...I think you may be confusing two functions. There is one that controls whether or not left and right buttons are reversed (useful for SCTs) when they are pressed, but on my Nexstar that only applies at the slower slew rates.
The positive/negative thing is in the goto approach on my Nexstar. It controls the direction the scope is moved in final approach to an object. My understanding was that it is related to backlash, as when you're doing a star alignment the mount is calculating the offset, and you don't want it to be counting slews in the opposite direction to counteract backlash.
Sounds like the gotos were just off
