I do not believe army movement is ‘simultaneous’, or that your first movement point is always on ‘day-one’. An old ME friend likened army movement to an “Impulse Movement Chart” we used in the old Star Fleet Battles.
Army movement has 14 days, or 14 impulses. In normal army movement, you get 12 moves - which begs the question; On which two days do you rest? Many players seem to think you move on day one and rest on the last two days - 13 and 14. I think it’s much more likely that your two days of rest fall somewhere from the first day to the fourteenth day, determined randomly each turn by nation or by each movement instance. Of course, if you plot a ForcMar then you rest no days and your first movement impulse is guaranteed to move. This idea may explain why “…I didn’t block him in the hex as planned…”.
Of course, I can’t prove this with data. I’d need both players orders to determine if this explained every instance. Furthermore, I have yet to meet a player that adheres to this theory. For me, his ideas always seemed to fit the circumstances and I could never disprove them. Doesn’t make him right, but certainly something to keep an eye on.
my 2 cents worth,