RonFrank:the fact that there is ONE approach to gear setup,
Ron
The reason for this is to keep everything simple amongst your dive team. If your configuration is identical then it is one less issue to be concerned with when you are in an emergency task loaded situation. It is an effort to reduce mistakes that can be made if your buddy has a different configuration. I've personally seen this happen on a few different occasions.
I hope this helps clarify why we choose to configure our gear this way. I also welcome you to ask me any questions about DIR. I will answer them to the best of my ability and if I'm at a loss, then I will put you in touch with others that can.