I'm not arguing this, but it seems counter intuitive to me. To me, "flight time" doesn't include time spent taxiing. If it did, wouldn't we all be entering the few minutes one spends taxiing the plane from the hangar to the shop? Or to the gas island?
I note the time when I'm cleared for takeoff, and I note the time I pull off the runway at my destination. That's what I enter in the books. I may be cheating myself, but I'm quite sure no one will ever be able to challenge the hours I have in my logbook. (Not that I'd care.)