Originally Posted by dozy
For the record, I was working off an old set of notes which were possibly incomplete
As you obviously don't have the tools, no more the knowledge or the experience to comment on how is working the A/THR on the bus, just quit on doing it. You create more disinfo than anything else.
The FCU button allows for a way to manually ensure that Thrust Lock mode is activated, which seems like a sensible thing to provide.
Another piece of your disinfo as no one is looking forward to activate the Thrust Lock function. That's something you want to suppress, not to activate.