Looks like you've done well. I don't know that you need to tweak the pressure settings anymore, if your AHI stays that low. You might experiment with the EPR. I don't know much about that, but from what I've read here, some people see a change in AHI, for better or worse, when they change the EPR setting. EPR is a "comfort" setting that provides a short "ramp" to full EPAP pressure when you exhale, as I understand it (Expiratory Pressure Relief, no?). At 3, you're at the highest comfort setting. You might see if reducing it does anything to the centrals. And see if there's any noticeable difference in comfort.
My goal is to feel more rested in the morning and less tired during the day. Since using APAP haven't had urge to nap so that's progress.
Three masks have been tried,
F&P Flexifit 405 (came with A10)
Resmed N10 (not able to lie on my side due to stiff mask frame shifting mask )
Amara View ffm - many issues with leaking and returned after 2 days
went back to the 405 and trying different pillow insert from Med to Large to reduce pressure on nose.
Have you tried a nasal PILLOWS mask, at all? It's much smaller than a full face mask or a nasal mask. It just sits under your nose (and blocks some of your mouth). The only pressure points on mine are the nostrils and some days, the top lip (the philtrum, is that?) But you have to be able to keep your mouth closed -- you probably are doing that already, since you say you have a nasal mask. The AirSense P10 nasal pillows (google it for a picture) has soft straps going around your head, but no real frame beyond an inch from the nasal pillows.
I wouldn't change actual pressure settings right now, but lowering EPR from 3 to 2 may help with the centrals.
If you are struggling with leakage your AHI and pressure settings may not be very relevant. I agree with Sleepster. You need to get the leaks under control first. Depending on the size and type of leaks, the rest of your data *may* be suspect.
Not sure if I would tolerate pillow style of mask like Resmed P10. Certainly will try them if no success reducing leakage.
Examining the leakage areas there doesn't appear to be apnea events nearby. Perhaps there is an impact on apneas but not sure. My goal is to reduce leakage to a minimum.
May try reducing EPR to 2 as suggested
Thanks everyone for the comments
Sounds like you are doing well.
Keep up the good work.