I've done the course. I've studied the materials (what little there is to study)
If I dive at 10,000ft, and treat a 50 foot dive as an 75' dive, the bottom line is that I still have the pressure of the water, and I still come up at 10,000ft which is well above the cabin pressure of 8,000 ft in a plane. Granted I live at 9,000ft so I don't have to adjust my pressure before the dive. I guess that is the major jist of it... You are at a lower pressure to begin with, and your body has adusted to that pressure, then once you come back up to the lower pressure your body will not off gas at an increased level?
IMO this all is not very clear, and in reality, there has been very little testing done on people diving at altitude.
Fortunately there is a LOT of divers that drive from Denver (5280') to the HOLE (4700'), dive their tails off, and then cross a 7,200ft pass without issue on the way back home. In my case, at the end of a Blue Hole trip, I end up at 9'000ft which is whre I live.
I think what the no dive to fly thing stresses is that you start at sea level, dive, end up back at sea level, and then jump to 8'000 feet cabin pressure. So you body jumps from presure group X to pressure group Y quickly as your body started at pressure group Z. (note: I'm using variable names for undefined variables, not actualy pressure groups based on the RDP).
In fact I'm not sure I, OR ANYONE really understands exactly how altitude impacts DCS in diving other than to say, it can be a bad thing.
