It is true that nitrogen loading is the same whether diving air or nitrox if you go to the NDLs, but it is also true that lots of people diving nitrox do not dive to NDLs. In fact, for lots of diving, it would be very difficult to dive to NDLs while using a rich nitrox mix.
I have many times seen people write as if there were only two choices while diving nitrox--either dive to air tables or dive all the way to nitrox NDLs. I have seen articles in major dive magazine (like Dive Training) that have said precisely that--you can either dive nitrox to air limits for safety, or you can dive to the nitrox limits for extended bottom time. You cannot, the writers insist, have both added safety and extended bottom time.
What such writers seem to be saying is that if you are using 36% nitrox and diving to 80 feet (using PADI tables), you must either end the dive at 30 minutes (air tables) or end the dive at 55 minutes (36% tables). You are absolutely forbidden to dive for 40 minutes to get both safety and extended bottom time! I don't know who is policing you down there, but, dammit, if you go past 30 minutes, you'd better make sure you have enough nitrox in your tank to get all the way to 55, because stopping short of that is not allowed.
I have many times seen people write as if there were only two choices while diving nitrox--either dive to air tables or dive all the way to nitrox NDLs. I have seen articles in major dive magazine (like Dive Training) that have said precisely that--you can either dive nitrox to air limits for safety, or you can dive to the nitrox limits for extended bottom time. You cannot, the writers insist, have both added safety and extended bottom time.
What such writers seem to be saying is that if you are using 36% nitrox and diving to 80 feet (using PADI tables), you must either end the dive at 30 minutes (air tables) or end the dive at 55 minutes (36% tables). You are absolutely forbidden to dive for 40 minutes to get both safety and extended bottom time! I don't know who is policing you down there, but, dammit, if you go past 30 minutes, you'd better make sure you have enough nitrox in your tank to get all the way to 55, because stopping short of that is not allowed.