| i had this a couple of years ago. I went to 1 min of no stop time, and it was all fine when I got out of the water. On download, it seemed I had missed 8 mins of deco, and I emailed Sven at Suunto. I can't find his reply, but it is all to do with the delay between what the vyper remembers, and what it tells you at the time.
As far as i remember, SDM recalculates, rather than remembers, the decompression schedule, when you down load. Because it is on a 20 second snapshot, it may show you as having missed deco.
If you change the interval in SDM, say, to 10 seconds, it will give you a different result - logically, in your favour.
Suunto were absolutely categoric in their response that what the computer tells you when you are underwater is accurate, what the SDM tells you is accurate but dependant on the sample rate.
One of the perils of diving close to limits!
HTH
__________________ Morag
YD Coven Witch One RNLI - YD Charity 2008/2009 Tin Rattler The Diving Club, Reading Shark Trust - Conservation through awareness I believe in Dragons, Fairies, Good Men and other mythical creatures  Anyone can make a mistake, said the Dalek, as he climbed off the dustbin |