Seeing the above makes me think the differences you see are due to finding a mask that your body just plain responds to well. If you body (and mind) *like* a mask, you will end up sleeping better - and in our cases, better also means in harmony with our sleep machines.
To be honest, I would like to see the same test ran on a 30 day trial, rather than just a ten day. But if it were me, I'd stop and just use the same mask (best choice) for the next 30 days to see if I continued to get the same results or not.
The final note in my mind that you did not comment on? How long have you been on CPAP? If you are a newer user, it could simply come down to becoming more used to the CPAP as a whole. FYI? I consider the first year as a newer user - your body may adapt to changes quickly, but CPAP as a whole takes time to adapt to.
*I* am not a DOCTOR or any type of Health Care Professional. My thoughts/suggestions/ideas are strictly only my opinions.
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