That's why I don't think of arrows as 'position changes'. I think of them as desire or eagerness to get forward (or back). An MR with a red arrow is still an MR in my mind, but its an MR that will get forward to an advanced position quicker or more readily (and use more condition doing it) than if it had no arrow. I also think that a MR with a blue arrow will still attack but when the ball is lost he'll get back quicker than if no arrow (but again will lose more condition doing so).
In my mindit also sits better alongside the Mentality settings in Orders. You can use mentality to make the whole team eager to attack then use red arrows to make individuals even more eager to attack. But thats just me.