As for the mounting pad, This is normal and has been done on all of our wheels. It increases clamping force / stress of the wheel. By doing this, the edge of the mounting pad touches the hub perfectly. When we apply the force by securing the wheel via the fasteners to the vehicle, the center area will go down and slightly deform (because it doesn't touch the other surface), thus creating additional force as it pushes back in the area where it touches the mounting pad. Hope this helps!