. But kaz, if my departure is 8 hours and 1 minute after the bottle, what prohibits me from doing unimpaired preparatory work as crew e.g. 1 hour before that departure?
Nothing if ... More than 8 hours, unimpaired and <0.02%
If my departure is more than 8 hours after the bottle, the criterion on which operation of the entire prohibition in (3) depends is not satisfied.
Remember sub (1) will get you if you are still stinky even after the 8 hours are up.