VERY interesting...and worth looking into. I guess I'd been assuming that this was the policy:
The DIR Fundamentals course is designed to cultivate the essential techniques required by all sound diving practice, irrespective of level or environment. Functioning as a prerequisite for all other GUE classes, save its recreational diver course (forthcoming), DIR Fundamentals performs a three-fold function within the GUE curriculum...
So, does anyone have any idea how often people successfully navigate this cross-certification process?