actually, i think everybody here is coming at the problem from different angles
DandyDon is coming from a recreational diver's perspective, and since those of us
who can't calculate our own ascent profiles have to rely on something, DAN's
guidelines are as good as it gets
JeffG is coming from an experienced, tech diver perspective. he knows how to
do his own ascent profile and doesn't have to wait around for what, with his
knowledge, is a waste of time (but Jeff, since i can't dupliacate your calculations
due to lack of knowledge, i won't take this trust-me dive uphill with you

)
GDI is coming from the instructor's perspective, and is concerned that those
who don't know what they are doing may get hurt. he's basically saying
that while some people can calculate their own ascent profiles, this is not
something to be embarked upon lightly by those, like me, without sufficient
understanding of the issues involved. thus, since there's so much
uncertainty for those of us who don't "know it cold," it makes sense to wait
i'm a lawyer, so i'm certain by now i've pissed all three parties off... but
so what? i do it on a daily basis eyebrow
my legal bill, btw, should arrive shortly