I think it's only visual.
For example if you set Wall (tanking) formation, they start from the sides of the field but then playing and marking oppo players.
Or attacking from all the space.
But the penalty in calculations-game mechanics still exists.
So if you put a DMC back or forth in the box, might starting from that position but doesn't affect game calculations.
But if you put an up or down arrow, this will add something in your defense or attack power (reducing the other side).
That's my personal believes.