I've been using CPAP for more than 6 years at this point and it worked ok when it did work. The reason it isn't working isn't because of fit, but because of the inflammation that it now causes. My machine has variable pressure, so it basically does what you have.

I taped last night and had the best sleep in a very long time, but it did have my legs issue, which had me up at stupid times anyway. My AHI was low to begin with as it started out as very high years ago.