Girod,
I find the method Norman Koren teaches to be much more useful when determining exposure "in the field." Norman is teaching you how to look at a color, determine it's relative luminance, and expose the shot correctly using your camera's exposure meter. Ron is showing you where the colors would display on the resulting histogram. Ron's point is that fully saturated red or blue will not display on the histogram the way that you would intuitively expect it to display, but will appear "under exposed" on the luminance histogram. If you (incorrectly) think you are underexposing based on the luminance histogram, and adjust your exposure accordingly, you will in fact be overexposing the saturated color. Using an RGB histogram (displaying individual color channels) obviates the need to use Ron's techniques to match colors to where they should display on the luminance histogram.
The bottom line is that Ron is teaching histogram based exposure techniques, whereas Norman is teaching exposure techniques based on your camera's meter. I find Norman's techniques for properly exposing color much more effective "in the field." (I also believe that Ron's information on the histogram display was based on Nikon tone curves prior to the D3 and D700, and may no longer be correct for those cameras.)
Hope this helps,
Keith
