Yes but when A/THR is OFF, ELAC maintains Vprot by pitching up and down.
If A/THR is ON, it would mean that both systems (ELAC/ATHR) are trying to manage 2 different speeds.
So in any case, ELAC should know if A/THR is ON or NOT.
2nd option: FAC is telling to ELAC if it has manage Vprot (A/THR OFF) or simply pitch sown and maintain any speed over Vprot (A/THR ON).
If ELAC doesn't know what A/THR is doing when A/THR is ON...sounds impossible...