Amongst other issues I'm trying to get my head around with the PC GS is the altitude offset. In the Syst Setup menu, there is the alt offset options. After reading and rereading the manual, I'm still in the dark. What exactly does " offset" mean? There is a height and elevation option. Height is altitude at ground level (AGL) and elevation is altitude from mean sea level ( Msl), right? If so, then what do you do with the recommended offset? Add that number to the altitude for each waypoint for the mission in the Editor? I'm flummoxed.