On these free-form headlights, it's important to have the right equipment for the job. Most places won't dedicate a level stall for the job to be done, which you'd almost have to have to do it on the wall. What most manufacturers recommend is an optical aiming tool, looks like a box with a lense on the front which the headlight beam shines through, uses some type of Fresnel Lens to imitate a wall at a far distance. It would be interesting to find out what process has been used to align the lights. I don't think MB actually forces a dealer to buy this equipment.