R S,
Not quite sure where you're sitting when it comes to maestro but a time is not locked in once you change it. It's locked when the flow or maestro 'freezes' it, but not before. I find it a major pain to be changing a time to better reflect what the aircraft is doing and to have to make a note of that time and to constantly change it because maestro persists in re-calcualting it every time it gets an update.
It is a dumb system that should rely more on radar derived data and controller input rather than having about 10 different parameters input.
I just don't get it, why spend all this money on a system that requires more intervention than before? Remember prior to maestro the flow set the order and we complied, if things weren't running to plan he'd adjust the order. Now we've got maestro, the flow, an en-root controller and an arrivals controller (multiplied by three feeder sectors and arrivals sectors) all adjusting and updating the elephant????
Stupid system complicated to make it look good to the customer!