If the a/c takes off from a remote location well above or below the Remote Controller (which is set as the Home Point), will it accurately set the RTH altitude relative to the Home Point? I.e., Are heights displayed on the remote controller relative to the RTH point? (I think so.)
GPS “altitudes” are not as accurate as their horizontal map coordinates, so I am skeptical of the accuracy of the RTH altitude in this case. I understand the a/c also may have a barometric altimeter, but little if any mention of this is made in your documentation.