Don, I think glbeas is color correct rather than b&w correct. Color head have Magenta, cyan, and yellow which are the colors of the dyes in color paper that are printed with green, red, and blue light respectively. Making red/cyan, green/magenta, and blue/yellow the proper opposites. But since b&w paper is orthochromatic the red of the equation gets thrown out which essentially makes your observation accurate as well.