I figured it out. The small washers are to allow the tuning shaft to drop inside the tuner housing via a hinged plate. I replaced the small washers with some not-so-small washers which prevented the tuning shaft from receding enough. I used sller washers and it's working properly now.
I am the recent owner of a new Spirit bass with the DB tuner. After a few days of tinkering with different string sets, the detuner quit working. Upon inspection, four small washers on the tuning screw were crushed and distorted. I have since removed them but the detuner lever seems completely disconnected from any mechanism inside the housing. Does anyone have an idea of what's going on inside the housing?