As far as my oximeter accuracy...
My sleep advisors had me spend one night with their oximeter (Nonin, I think). I also 'wore' my oximeter the same night (slept with both of them on my fingers). I am hoping to see what kind of a correlation my oximeter gets with their oximeter.
One more comment on oximeter accuracy:
I had my wife put on my oximeter tonight for about 5 minutes. She watched the display and got a range from 93 to 98, mostly in the 94 to 95 range. I then put it on my finger and got a range from 89 to 92, mostly in the 90 to 91 range. I don't know if this proves anything, for what it's worth.
I smoked a little from about 1964 to 1969 (maybe half a pack a day at most and some days hardly at all). I have not worked in dusty environments that I can remember. As I mentioned before, I had pneumonia 3 times (1ce with bronchitis) and played really loud tuba in German bands for maybe 25 years. It's my understanding that pneumonia can do permanent damage to the lungs -- maybe I'm wrong. One more thing, my father was a chain smoker (unfiltered Chesterfields most of the time) so I got to breathe a lot of second-hand smoke through my growing up years in the late 1930s through mid-1950s. Also, with my band playing, in those days everybody smoked (I didn't most of the time) and the dance halls we played in would develop this stationary, very heavy, cloud of tobacco smoke, which I had to breathe (more second-hand smoke aplenty) for usually 4+ hours (sometimes longer) a night. Now they say that breathing second-hand smoke can be bad for your health -- they didn't know that back then. Maybe the 2nd-hand smoke did the same kind of damage as dirty air could have done.
Thanks for all your help! Hopefully the minimum pressure tweak will result in some significant improvements...