The waypoint only resides on the home unit. It is not transferred from the remote unit rather the home unit uses the remote unit as a secondary waypoint memory device and can therefore display the remote waypoints.
Let's only consider all the waypoints residing on only one units, the home unit.
"the home unit uses the remote unit as a secondary waypoint memory device and can therefore display the remote waypoints."
Do you mean:
"the home unit uses the remote unit as a secondary waypoint memory device and the remote can display the home's waypoints"? As in the remote "pulls" the home's waypoints that the remote needs to display?
Because in the case of the remote display, only the remote "knows" which waypoints should be visible on its map display.