time difference between machine and software

[sheepless]

I haven't used resscan since 8/5/18. your question prompted me to resurrect v.5.7:

daily usage time is the same as reported on the machine. pressure graph begins at the same time flow begins. no lag. oscar and sh always report less time and show a 41 second lag between when flow and pressure graphs begin for each sleep session.

[sheepless]

IDK if there's interest in this issue but thought I'd update.

I've concluded that the pressure graphs always begin 41 seconds after the flow rate graphs.

there isn't a clear or consistent relationship between the number of those lags (number of sessions) and the differences in total time reported.

for the first time (that I've noticed), the times reported last night by the machine, Oscar and SH are the same. last night was unusual for me because I had just 3 sessions, probably the fewest in more than 2.5 years of cpap. unfortunately that still leaves 123 seconds (3 sessions x 41 seconds) of gaps unaccounted for.

I'm at a loss for clues to explain these discrepancies.