Dear Mac, your above argument may be correct, as some variables are independent and some may not be. Your example of potentially increased risky behavior (especially for males) at the younger age has been brought up at this board before and is likely true. It is also possible that 30-39 year olds have collected a lot of experience (or may think they have) and diving more aggressive profiles and may put themselves at higher risk.
The way I think about NitrOx is as someone is giving you a head start in the race, except the total is your nitrogen load. If you are Usain Bolt , you don’t need a head start, but most of us mortals could use it (some more than others)
Other than MOD I don’t see a disadvantage of NitrOx.
Now if you want to argue cost effectiveness, or as we call it number of patients needed to treat (how many divers need to use NitrOx to save on from getting bent) then it is a different argument and we can probably do some calculations for that