When you are talking about the bar and the Aircurve cutting off before you are done inhaling, I had the same thing. IMHO it's not the T1 time but the T2 time. T1 sets the minimum that the Aircurve wants you inhale to last. The Aircurve T2 is the upper limit and if you try to inhale longer than that the machine drops the pressure to try and get you to stop inhaling.
My T2 was raised to 3.2 and that was much better, but I still found myself waking during the night with the same feeling (kind of like someone was putting their hand over my nose right at the end of my inhale). I bumped my T2 up to 3.4 and at last good seeping with VPAP.
I figured this out by putting the mask on with machine running. Getting a good breathing pattern going and then looking at the bar. Every breath I would see the bar retract right before the end of my inhale. I also looked at the plots of when I was asleep and measured the time for my inhale, I inhale slowly, more so when I am asleep.
Insp. TimeTime taken to breathe in (Seconds)
W-Avg: 1.48 0.00 1.48 1.82 3.40
Exp. TimeTime taken to breathe out (Seconds)
W-Avg: 2.07 0.02 2.06 2.60 5.86
This is from my latest sleepyhead with an AHI of 1.48
Yep timax. if you feel like it is cutting off your inhale, then yes increase it unless your Doctor is trying to shorten your inhale. They do that sometimes with COPD, if not extend it and see when you get a full inhale.
The cycle setting adjusts the machine's sensitivity to the change from inhale to exhale.