Interesting to see the differences in mounting hardware between shops... The conical seat on Mandrus likely has to do with the fact that there are differences in bolt thickness among different Mercedes models. IIRC, some E-Class and S-Class use M14 bolts. SLK-Class, C-Class, and the Crossfire use M12.

So from a production standpoint, it makes sense to have a M14 bolt hole on the wheel with a conical hole. The angle of the seat means there's a positive hold once tightened, regardless of lug bolt diameter OR bolt length per specific vehicle model. Once the bolt is tightened to 80 ft/lb, it's good to go. The ball seat used by MB works when the bolts (M12/M14) are engineered to mate to a specific hole size in the wheel intended for that model.

Mandrus makes a quality wheel, so even though the hub is thinner, it's by design to accommodate the entire MB lineup.

If the 24mm length bolts work on your car and allow you 80 lb/ft of torque per bolt, you're in good shape.

Happy cruising.