Picture the scene. A nice, rural road, 5cm across, bounded by linear obstacles either side. A unit of infantry is lining one hedge, so has 2.5cm space behind it to the next hedge. It's suppressed, then forced to fall back 4cm.
Does the unit
a) Fall back to the obstacle and stop
b) Fall back to the obstacle and is then destroyed as it cannot pass through it because it hasn't halted at it.
c) Fall back the full distance
d) Some other that we couldn't think up.