To refrase it... If you were interested in doing deco dives (Forgetting the PFO for a moment) to get longer bottomtimes at 25-30m, but not interested in going deeper... How could you get certs for other gases than <40% Nitrox?
Or is >40% ONLY meant for those going 35+?
Hmmmmmm. . . . isn't MOD for 40% 30m ? (if ppO2=1.6) !