I happened to have a Quatro FX that I used last night. The results are somewhat better but I don't think it's right. When I put on the either mask, they seem OK at first not tight and the 'skirt' inflates and I don't notice leaks. I then move the mask around to see how much tolerance there is for leaks. Then off to sleep. I'm usually awakened an hour or so later with the mask seeming to blow off my face and making a helluva whoosing noise. It's like the S9 is starting LiftOff. I've tried manually forcing the mask against my face to see if the pressure will eventually go down but it doesn't. I then cycle power on the S9. I can repeat this several times and then I just give up and put up with the apneas.
I know I must be making this more complicated than necessary. I've attached several plots from Sleepyhead in the hopes that you can spot some obvious problems.
imgur.com/mWCm98Z.png Quatro (the first data is me trying the mask first to make sure it was working)