Ground lead was never allowed to give us the “Stop” signal while backing. Instead, it was a “come forward” signal that he/she would give if we needed to stop immediately while powerbacking. With our feet on the floor, the captain would close the reversers and add something like 1.2 EPR(DC-9/717) to stop backwards movement and come to a stop. Nighttime power backs were always interesting. It is like those runway turnoff lights on the Douglas (they had a momentary push in type action and were placed on the forward fuselage) were designed for the wave off signal at night during power back/taxi clearance. Was fun while it lasted.