Move your unit until all movement is done. Mouse around, the computer says 1 turn, but it is red showing it can't be done.

1 indicates I can move there taking one turn (or a programming bug.)

Red indicates I can't move there this turn.

As a programmer, you can say that is one turn away, but red says that will be next turn.

As a user, I'm going to be able to reach them on turn 2, and red confirms that.

I'd rather they were consistent myself Red or 2+ means that I can't move there, it's less confusing than the red/green and 1/2 dichotomy.