Oh, thanks. So, I guess I should look at the graph.
But there is not anything special about the 18th hour vs the 17th hr or the 19th hour, is there? Maybe arbitrary is not the right word.
I think sometimes people become nervous when divers "break the rules", even though had the OP followed the rule to letter, to the hour, yet not hydrated and rested adequately, I would think that would have more of an effect than diving on the 23rd hour instead of the 24th hour. We just don't have a rule that states "Force Fluids and drink "X cc's/ kg" post flight" and sleep X hours before diving (like the pilot rules, etc).
Still, it upsets people to some degree when you "break a rule" even though perhaps other factors might matter even more. I believe that if you are a thinking person and in control of other factors, like your health, and managing those risks, fudging an hour is reasonable.
The guy that goes to the wedding, drinks all night and doesn't sleep can't afford to think like that, IMV. Part of being prudent is knowing what kind of person you are before bending the rules a hair.
The thing I thought was insightful and prudent of Kris B post, was that he clearly identified a more probable risk (dehdration/fatigue VS an hour in the grey zone) in the proposed scenario, which is often just the type of thing "devout rule followers" miss, just because no one as issued an "official" mandated rule.
