floating time zone

Does anyone know how to fix the problem that a floating time zone would fix? I read all the old posts and, like others, I do not see “floating time zone” as an option. I travel a lot and have to put in the time zone of each item per destination as well as the time zones of the departure and arrival cities. Seems many people have requested this floating time zone. Apple programmers are Geniuses in my eyes. Is this too difficult for Apple to implement?