Can you give an example where or how the squad positioning was inaccurate?
Without knowing that yet, I'll just throw here that depending on what the environment is like, the squad members try to keep a distance from each other to not to clump up, so getting the whole squad to a single position should not be possible to achieve accurately. Because of that the markers need to be thought of more like hints.
They also might try to locate cover in the surroundings of the marker, but honestly I don't remember if they do or don't
Another thing that affects it is if you were in a battle while your squad didn't appear to move to the position. If they were fighting, it's likely they were distracted not to follow your orders, or, maybe they were already fighting against an enemy in the direction of the marker, hence not being able to move towards the position; you could try to double tap (or re-tap at the same position) to boost the command. They practically should charge towards the position then, risking their lives by leaving the cover they might have gotten in to in the battle.