If I correct for shadows then the skin tones become to dark and unrealistic. The darkest area of a fleshtone does not meet this description. Hence, having both of the above numbers in the same image is not necessarily incorrect. I think what may be throwing you is that the M and Y values are higher in the dark fleshtones than in the shadows. Let me try to explain why this is reasonable.
Many printers insist on an absolute limit on the amount of ink put down in a given area.
The number is governed by CMYK Setup in Photoshop 5 and Separation Setup in earlier versions. You will note that in your current shadow the values of all four inks sum to 300. Photoshop will artificially suppress the shadows in the color plates in order to stay within this ink limit. In your dark fleshtone areas, on the other hand, cyan and black are relatively weak. Therefore, you cannot go over 300 even if the yellow and magenta are 100 apiece.