Quote Originally Posted by AgX View Post
So far I thought such "Color" designations reflected a better lens-design concerning spectral aberrations. Am I wrong?
By spectral aberration, do you mean chromatic aberration? If it is the case, the lens coating does very little. You can't fix an optical aberration with coating as coating is not supposed to change the lens characteristics but only improve the light transmission and reduce flare which is some cases can improve color fidelity.

Regarding different comments about visible improvement from coating, I also noticed that single coated lenses were good enough at least for the type of pictures I take.