Lots of bad answers here. The clamping effect of a bolt is determined by elastic deformation. The more the bolt stretches, the tighter it holds. If the bolt is dry, the threads and head generate more friction than if they are oiled, which should be one thing that’s obvious to everyone. As a result, it takes more torque to achieve a specified strain when dry than it would if the bolts were slippery wet. So if you oil the bolt, tightening torque must be reduced or you can exceed the point of plastic deformation, which is where threads strip and bolt heads snap. Once you oil the bolt, the manufacturer’s spec is out the window, so you’re on your own. The only thing that’s saving some of you is that Mercedes assumes clueless mechanics and designed the system with some reserve.