When I was at America West the ACARS captured 5 time events. (Push, Out, Off, On, In)

PAY BLOCK = pushback brake release to arrive on gate brake set.

BLOCK TIME = the 2nd brake release (motors running, doors closed, etc) event until arrive on gate brake set.

FLIGHT TIME = rotation to touchdown.

That was over 3 years ago and prior to the marriage with the East, so take that FWIW.

Also when ACARS was turned on for tracking times, the initial system did not account for that "pay" time duing pushback. As I remember it ALPA was able to prove that past practice had been to pay crewmembers during pushback. So the system was altered to capture those times described above.

What they do now is anyone's guess ...

But I do remember there were only a few times when PUSH time was the same as OUT time. When a ramp parking with airstairs was used instead of a gate with jetbridge. Start-up and taxi without a pushback meant PUSH and OUT were the same time.

BrownBus described the system at UPS.

Just for clarification ... Are you calling for pushback and releasing the brake at 1500z. Ramp responds hold your position for traffic. Then you receive actual pushback clearance at 1515z when the alley clears. So your "ramp operations" goes back and adjusts the aircraft "OUT" time to 1515z ?

In spite of another poster's opinion on the definition of block time. I think it is a definite "grey" area for a company to routinely go in and alter ACARS transmitted block times whenever it wants to. What is their official clock ? Who is observing the aircraft movement ?

Either ACARS is the official timekeeper or it is not. It is typically an FAA aproved system. I don't think you can chose to use it when you want and ignore it when you want ... MEL situations aside.