It takes about a minute to push and start an engine and begin taxiing. Maybe a few mins waiting to push during bank time in phx. That's a wash. Plenty of times I've sat waiting for a gate driver with an inop apu babysitting an engine with the pax door open. That is creditable flight time by FARs but not on the acars. But I don't add that to my logbook. The minute difference doesn't make much of a difference, especially converting block minutes to decimals. If you care that much about that minute, round down on your conversion to decimals.