hmm... when I hover over a single event on the timeline, the number in the parens seems to match what I see on the timeline for that particular event. I wonder if you are zoomed out and multiple events are scrunched together, making it difficult to correlate which event SH is telling you about?
If you have already explored that, then I believe what you are saying as I have not played with this feature as extensively as you may have done.
how interesting. I see what you mean, my Sleepyhead does the same thing on the top line Event Flags chart.
Check out hovering over the events in the Flow Rate and other charts below, they seem to behave better. That's where I was playing around when I posted earlier. The Flow Rate chart is the one I mentioned that when you hover over an event it draws a box around the timeline representing the number of seconds reflected in the parens.
I just noticed that the Mask Pressure chart also has event flags which show the correct duration in parens but the highlight doesn't span the duration the way it does in the Flow Rate chart.
I think you might have found a bug in SH on the top line Event Flags chart.
With its few little quirks, still an awesome useful tool.