Maybe theoretically, but not in practice. In the prepress world is common to use the four values of CMYK, for example in 'rich black' (http://marvin.mrtoads.com/richblack_vs_plainblack.html) or in PANTONE to CMYK transformations.
Thanks for the link, it is interesting. But is all this fuss with different black colors really necessary? I would suppose that the designer should not be bothered with such matters and that the printing device should solve the corrections resulting from the fact that 100% of ink does not filter 100% of the light but, say, only 80%, and so the ideal CMYK 0,0,0,90% must be replaced by 50%,50%,50%,80%, which means 62.5%,62.5%,62.5%,100% of the maximal amount of the ink. After all, the color space perceived by humans is 3-dimensional and so there is no need to use four coordinates.
P.A.