Headlight adjustment: mechanics defective?

Yesterday H4 lamps replaced. Now a headlight adjustment (height) is necessary, since the piston of one of the old lamps sat obliquely on the plate (production error or workshop mess during installation?) and the headlight was probably adjusted to suit this “sloped” lamp. Vlt. also the previous owner murmured the lamp in? The height adjustment made no sound today. I tried it again at the height adjustment screw, after I had the headlights over the St illmotoren, i.e. setting “Vehicle fully loaded”, completely shut down. Also in this reflector position I can turn the adjustment screw without results. On the other headlight the (also) smooth adjustment screw behaves exactly like this. I am surprised that this is the case with both headlights. Does anyone have an idea? Thank you in advance!