IIRC a S9 Autoset won't help much with CAs. Talk to your sleep doctor, as if you're seeing over 5 you need to figure out what's going on. You may need a more advanced machine to help with your CAs.
Are the CA's scattered or do they occur at or above a certain pressure? Are they occurring at the beginning and/or the end of your sleep cycle?
One experiment that you may try is reduce your EPR to 1 for a week and then 0 for 1 week. The EPR can contribute to CAs since it is a type of pressure support on a bi level. If after reducing APR to zero, your average CA index for 7 days still doesn't drop below 5, then you need to be reevaluated via a sleep study for a different machine that can take care of CAs for you (probably an ASV machine). FWIW, Medicare does have a criteria for this.
My 2 cents. YMMV.
Started APAP 4-20, Closed range to 7.5-14, then straight 8.0 w/ Aflex 3
RDI always below 1. But sleep much much better at straight pressure.
Started on F10, Tried Quattro Air successfully. Finally settled on P10.
You may have complex apnea, and regardless of the cause, you need to consult with your doctor to discuss the options. Somehow I doubt changes in EPR alone will change the results. On a "good night" you marginally meet the criteria for being treated. On the bad night, you have moderate to severe apnea with CPAP.
You didn't answer my previous question if you had a titration study. Did you?
I did the titration study (not split), and it recommended CPAP at 13. I specified the APAP since I figure one night of titration is not a real world simulation, not the variable position and adaptation once you've used a PAP for a week or two so I wanted the auto to be able to adapt and settle in at the most appropriate point. I started at 6-16 and tightened to 9-16 after I had some data showing the average and 90% pressures. This big question is what factors are affecting the good vs. bad nights, which hopefully I might get a handle on if I start a diary.