The software also shows that I have been using the mask for 2:44 hours when I actually used it from 2 AM to 12 noon! I sleep and use the machine for the same number of hours almost every night at the same times (1:00 AM to 11:00 AM) and the time that it shows ranges from the correct number of hours to 8 hours less than I have used it. That must through off all of the readings.
My machine does the same ting. I have been wondering about it. Don'[t see how it matters terribly in the end . . . . but make me wonder what the machine thinks it is doing.