That's the theory-but there were obviously exceptions here and there-hence the "exact count" by Kleitman. Chris. B. is the author of the black/white ribbon for auslandsdeinst and this seems to have been backed up by some language in a book I have. Still, it'd be nice to have a specific regulation or directive to point to-or documented groups as proof positive.
I too have seen the Ludwig cross/black/white EK2 combo and while some seem to be "newly made" combos-others are not as this photo demonstrates. Now, if we could just figure out this mans' career.