For the first problem, the chopper needs to reach a destination where the fine landing code takes control over it. If the chopper doesnt reach that destination because it is fleeing away or fighting, the accurate landing code is not executed.
About the locality, for example, if you start inside a chopper piloed by AI, the first second of the mission the chopper is local to the server, after this, the chopper is local to the player (cargo) inside.