Not sure you want to push that too far! What is the FAA definition of (Block) flight time? I believe you will find it says that it starts from the time the aircraft moves under it's own power to the time it stops moving under it's own power. Neither push back nor tow in are included.
Electronic Code of Federal Regulations:
PART 1—DEFINITIONS AND ABBREVIATIONS
Flight time means:
(1) Pilot time that commences when an aircraft moves under its own power for the purpose of flight and ends when the aircraft comes to rest after landing; or
(2) For a glider without self-launch capability, pilot time that commences when the glider is towed for the purpose of flight and ends when the glider comes to rest after landing.