Lomont:
First off we're talking recreational dives which are in theory within the no-stop limits. Notice I didn't say NDL or no decompression limits. That's because if you get compressed you will decompress. ok?
Lets first address the idea of deeper stops whether the NAUI (rule of halves) or stops at 30, 20 and 10. I see 2 benefits. One is learning to do the stops. The second is the fact that we're stopping deeper which the bubble models suggest is a good idea. Without going into a bunch of detail all else being equal a higher ambient pressure will keep a bubble smaller. Note, I said all else being equal.
Why bother on a rec dive when we have a table in our bag that says we can ascend directly to the surface at 60 fpm?
My answer is that we know from doppler testing that there will be bubbles after a dive. Maybe a problem and maybe not but what about the next dive? What about your second or third day of multiple dives in a row? As far as I'm concerned less bubbles and smaller bubbles is better.
So...even though a table only considering max depth and total time might assign a pretty high pressure group the fact is that if some of that time was spent shallow you could surface pretty clean and if we do it right we can address bubble growth which the table doesn't know anything about. You decompressed more in the water, under pressure, rather than on the surface at 1 ATA even though the tables or your computer told you that you could go to the surface.
