IIRC, there's an old thread on SB about Vypers and/or Cobras spinning up the CNS clock super fast just a tad bit too early. It looked to me like it was going to 10x speed at 1.4bar rather than 1.4atm, so you had to be within a foot or two of the 1.4ata MOD to be in the strange condition where you didn't have a high ppO2 alarm, but the CNS clock was screaming along at warp speed. The manual said something about being accelerated above 1.4ata, but the original poster was shocked that Suunto chose to allow only 1/10 the NOAA allowed time between 1.4 and 1.6ata ppO2.
People also get confused a bit by the Suunto practice of the diver truncating the measured %O2 before entering it,then the computer using the next % higher for MOD/CNS calcs. Example: For any O2 analyzer reading from 32.0 to 32.9% you enter 32. Computer uses 33 for O2 calculations, 32 for N2 calculations. Makes good sense to me.