What us going on here two days same settings?

[Ohiosnoring]

Hi, Thanks for a very informative community. 
Been at this 7 months thought I had it locked.
I know my apnea is highly position dependent.
My sleep study said 52 AHI prone  and 11 at other times.
I have moved to F&P Vitera as I was a mouth breather and use a chins strap that provides vertical tension and support. Above about 14 I get aerophagia but grape seed capsules seen to help the following day gas.  I have epr off and am comfortable with that. I have no ramp and falling asleep is not much of a problem. Not overweight,  don't drink, perhaps I should, lol. Have tried wide range 9 to 16 abd 95% is usually around 12.8 to 13.5.
Do have some flow limits issues but don't understand as with wide range machine could use the headroom in the range but chooses not to.
So how can similar setting produce such varied results and what should I change, thanks?

[Ohiosnoring]

Second image same settings.

[Deborah K.]

One night you had terrible positional apnea, the other you did not.  As I think you know, positional apnea cannot be fixed by a setting.  It is caused when your chin drops toward your chest and is much like a kink in a hose, but you block airflow instead of water flow.  For some a flatter pillow will work but most need to wear a soft cervical collar.  If the size is right the collar will hold your chin up and give good results.  A lot of us like the Caldera Releaf Collar as it is comfortable and works unless one needs a high collar.

Unless the night with positional apnea was a one-time thing, you need to treat it.

Also, you ought to reconsider using EPR.  EPR lowers flow limits, which are short-time apneas that are not reported as apneas but need to be treated.

[SarcasticDave94]

EPR 3 full time will give you a tool to help reduce flow limits. By doing so, your Auto CPAP/AutoSet becomes a bilevel.

[Ohiosnoring]

Hi, Thanks for input. Now have Cervical collor and chin strap. Have epr at 2. Have raised bottom pressure ftom 11.6 to 12.8 to compensate. My numbers are much more stable at around 2.5 most nights.
I have also taken steps to make sure I sleep on ny side most if the time. If i extract the 30mins before waking its about 1.75. Flow limits are at .02 so that is fine. My CAs are are 2.4 ish would like to control them better. Yes it is mostly positional with me as you suggested.