My Suunto computers will subtract a 0.1 or a 0.05, not sure which, automatically from the Po2 you dial in the computer for added "safety." When they do the calculations and display NDL and MOD, they will lower the O2% by 1% to give you less NDL and will lower the Po2 (or pretend that you have higher O2% than what you dialed in) to make the MOD shallower. With both tweaks in the Suunto software, the computer will be more conservative.
