For a movement macro you need to start at the same starting point. The macro is just the required moves to go from point A to point B. Unless you're at point A, it won't work.
With auto-center on the map, it doesn't matter where you are, as long as you're on the path. The map just starts the macro at the correct spot.
Occasionally, when you were running through an area, you would get attacked, interrupting the macro. This way you could just restart the macro after the combat and it would pick up from the current location.