RE: First Sleep Test
Can you think of anything potentially relevant that changed this past week? Bedding? Medications? Allergies? Sinuses? And is there any chance your chin is sometimes sneaking down the front of your collar?
You can try inching up your minimum. To start with, you could try a minimum of 16. With luck, a small increase in the minimum will manage to head off some of the OAs before they can get started. After maybe 4 or 5 days with 16, if you see no change, try 16.4, or a little more if you can hack it.
RE: First Sleep Test
Well, what a shame; things were going so well there for a while. How long have you had the minimum at 17.2? If it hasn't been at least a week, then I'd say stick with it to see whether the OAs will come back down for some reason unrelated to your settings.
If you keep having an AHI above 4 (which is where you start feeling lousy the next day), then I do think your minimum needs to come up a little more. You can either keep your EPR of 3 and raise the minimum pressure setting, or you can try reducing your EPR to 2. What you're looking for is something that's effective and tolerable.
RE: First Sleep Test
I don't see any particular value for you in switching from APAP to CPAP. You could try going up on your minimum pressure a tiny bit; if it's tolerable, give it a couple of weeks to see whether you think it's producing improvement.
Could you remind me: do you mostly sleep on your sides or on your back, or is it some of each? You're still having some mini-clusters of OAs, and I know you didn't get along with a collar, but you might have a better night if somehow you could address whatever positional issue there might be.
It'd be good if you could get the leaks under control. Do you think they're mostly from the pillow interface, or mostly from your mouth? I know you don't like a collar or tape, but has tongue position come up earlier in your thread? If not, here's the deal:
Put the tip of your tongue behind your upper front teeth. Then position the main part of your tongue up against your upper palate. Finally, give a little suck or swallow to create a bit of suction. You should now be able to open your mouth while breathing entirely through your nose. Practice this during the day, and see if you can get it grooved in deeply enough to help while you are asleep at night. For some people, this is really all it takes to avoid mouth leaks.