Well I think we have come full circle and narrowed things down a bit. You started off with settings of 5-20 and EPR at 2 and had lots of CA with AHI at 12.66 and max pressure never went above 10 cm. At fixed 10/8 (EPR 2) AHI was 8.2 with about half OA/CA, but good tidal volume at 480 mL and respiration rate at 13.
At fixed 12/10 (EPR 2), you had 7.66 and were uncomfortable with exhale, and events were mostly hypopnea with some OA, and your resp rate shot up to 39 BPM and minute increased to 10.25 (tidal volume was cutoff in chart)
At fixed 8/6 you slightly increased events to 8.29 with an increase of OA vs H. Leaks are not a problem, but you have a lot more FL and snores as well as low volume during periods of obstruction. Your minute rate was 8.12, tidal volume at 300 is not ideal, and what is up with that respiration rate of 24.8 BPM...
I'm a little frustrated that we are not making positive progress. Your results are all over the place, and are contradictory to expectations. For example, I usually expect to see fewer central events at lower pressures and fewer obstructive at higher pressures. I can't explain what is going on with your respiration rate that appears to become erratic at higher pressures. I suspect this is an error but would need close-ups of the flow rate to see what is happening, and why did this happen at 12 and 8, but not at 10?
I think going back to auto pressure at 8-14 with EPR at a comfortable level may be the best I can suggest right now. You need to have more time at settings to see what the impact of that setting is, rather than reacting to one night as we seem to be doing now. If things don't settle down to a comfortable and effective level, you may need a professional titration study where alternatives can be looked at. As I recall, you had two sleep studies, and in the first study, you were found not to qualify for CPAP, and in the second, CPAP was recommended at a pressure of 10. The inconsistency is continuing. Very puzzling.