Good points.
So as I see it, the variables (so far) might include:
Conservativeness -- Cautious/Moderate/Confident (eg: time at depth; 1min/3min/5min?, assent rate; 1atm/min, 1.5 atm/min, 2atm/min?, normal RMV multiplier:x1, x1.5, x2?)
Units of measure -- Metric/SAE
Extra stop?
and the...