Not sure I totally agree with everything you are saying. My drain pumps are mounted below the rear locker floor so there is more hose between the bag and the pump compared to Berg's set up and I have never had any problems with draining the bags. I always just make sure I pull the bag away from the rear ski locker wall enough so the 90 degree drain fitting has room to lay flat. I always thought that the fact that the pump is mounted below the bottom of the bag means there is positive pressure going into the pump so it does not air lock. Anyway, my drain pump set up from the factory has always worked flawlessly.