Costco has such leader boards and keeps a separate board for part timers vs full time cashiers. I asked my friend who works there why the part time cashiers hav

Costco has such leader boards and keeps a separate board for part timers vs full time cashiers. I asked my friend who works there why the part time cashiers have a much higher (upwards of 2x) items per minute rate than the full time employees. Costco only schedules part time cashiers during busy hours where the lines are long and there are assistants getting the carts ready.