Thanks Mike.
I hadn't thought of the idea of setting my devices to UTC, so I liked that idea at first. Then I wondered what would happen to the Winds Aloft forecast based on a location in Central Time, UTC-5, but analyzed at UTC-0. I bet it will mess up the forecast.
Going from Flight Plan to More Options, Altitude Planning, there is a slider for departure time, at least for the purpose of windowing into the right set of wind data. I just now entered the Online Filing tool and found that clicking the departure time field opens a keypad for precise entry of departure time. I made a flight plan from DeMoines to LAX just to see what happened. Per the screen snip below, I depart at 6am central time (UTC-5), fly 12 hours, and arrive in LA at 6pm, also in Central time (UTC-5).
I too noted that the flight plan log only shows point to point ETE rather than ETA. It would be nice if ETA was added and like you say, dynamically updated (and I would hope in UTC).