Carl-For whatever it might be worth, I understood what you were saying from the begining. You NEVER said anything about what units were listed under DIU, only what units were shown under receivers. I noticed exactly the same thing and wondered what receiver one might get by doing a DIU. I've got a 622 & 722 and thought about swapping the 622 if "Enhanced" HD DVR meant the 722K. I experienced the same confusion as you when I looked under HD Receivers/DVR Receivers.
Seems to me some folks are all to ready to jump on someone before comprehending WTH they're saying (typing?).
Good luck and let us know what happens if you do the DIU roulette.
Ed