Regarding the possibility of higher pressures (potentially) causing pressure-induced Central Apneas, for all intents and purposes, only people who are susceptible to them would have them occur. Typically, the Centrals would have been discovered during a sleep study and even more typically would occur in pressures lower than what you're using. And, roughly only about 15% of users MAY be susceptible to pressure-induced Centrals.
Another thought or two came to me. Have you checked your machine to see if it's putting out the pressure it's set to?
Your profile shows you're using a ResMed S6 Lightweight, which is not data capable. Do you have another data-capable machine (or access to one) so you could see some data to see how your settings are treating you? Fully data-capable machines aren't all that expensive and can be acquired pretty easily.
Checking your machine's output can be done pretty easily and cheaply. If you go up to the "Advanced search" and do a search on "manometer" with the Author as "tomjax", you'll be able to find how to do it with a bucket of water and a ruler.