The vehicle efficiency and range data that Tesla submits to the EPA is collected solely from dynamometer testing. There is no air resistance, headwind or tailwind factored into the test results. When Tesla decided to remove the Low regen driving setting it was not due to vehicle drag force.
I don't think that you can ignore the time component here. Strong regeneration might lose a little more to electrical losses, but it saves time by allowing you to travel longer and further at the target speed (perhaps the speed limit) before stopping. Coasting to a stop or using lower regeneration might save energy, but you'll more than lose it by needing to go faster to keep the same schedule.