That are still some doubts that need to be clear and sadly I can't experiment in the last 2 most important match of the season. For example take a plain 442 formation. when you move your DR and DL forward to the edge to simulate arrows up the game will consider the defenders line up as 2-2 instead of a plain 4 this means the DR/DL are playing as DMR/DML's (this was an illegal formation you needed minimum 2 defenders) but now the game does not tell you that it is wrong.
Other thing is when you move your MC back near the DMC position you will see that the zone gets slightly brighter, this basically is the same with all positions.