Bunkers Trenches Improved Positions

[Fortynslow]

One thing I have often wondered is the rationale behind the downgrading of these positions when vacated. It is probably something really simple but I must confess to never really understanding the why?

The attacker is typically moving in the opposite direction as the defender, meaning, if the attacker would need to take up a defensive position against the enemy's counterattack, the fortifications would be orientated in the wrong direction.   Bunkers only point in one direction, reverse slope positions become front slope positions, defensive positions sited against likely avenues of approach from one direction are not necessarily oriented towards likely avenues of approach from the other direction.  If anything, in my opinion, 50% is probably too beneficial.