Hi takata,
When trim is activated manually, autotrim is frozen, can't displace anything anymore.
I can't find any reference to that - it would appear to be in error.
How would the computer "simply displace the elevators to a new "null position" and "trim the new attitude" without changing the THS setting?
In the same way the system copes if the stab is "frozen" in a position with the loss of the relevant hydraulic systems.
Similarly I'm saying that if the stab trim is held stationary, it makes little difference to Normal or ALT LAW in pitch, because the elevators will be repositioned to compensate - until they run out of authority.
edit.
In fact, it is a case calling for more automation as some would have liked that this aircraft could be able to determine all by itself that pilot's orders were stupid and should not be followed by any aircraft stupid control surfaces.
The design of Pitch stable Law
without Alpha Max protection, on an aircraft which is inherently naturally speed stable (by design concept), during UAS is not logical. Why would you want to do that?