Hi @mark3240, Welcome to Connect. My AHI varies a little but normally between 1 and 4 events per hour. I have a ResMed AirMini with no tank and I use a full face mask with a cloth comfort cover so I do have air leaks. They don't make much difference for me. When my AHI is higher than normal I sometimes find it's because I have been sleeping on my back and I normally sleep on my sides.

ResMed has some information here that mentions Central Sleep Apnea may be the reason for high AHI numbers.
"Central or complex sleep apnea: A rising AHI could also be a sign that while CPAP is treating your obstructive apneas, your brain might not always be telling your body to breathe. This can cause central sleep apneas, “central” because your apneas are causes by a dysfunction in the central nervous system, not a physical obstruction. Most newer CPAP machines will report if you’re experiencing central apneas or you can’t identify what is causing your rising apnea-hypopnea index, talk to your doctor or equipment provider as soon as possible."
-- Why does my apnea–hypopnea index (AHI) change?:
https://www.resmed.com/en-us/sleep-apnea/sleep-blog/why-does-my-apnea-hypopnea-index-ahi-change/
Have you mentioned the high AHI numbers to your sleep medicine doctor or care team?