I have to adjust my own pressure as well, since I can't afford to do another sleep study (American Healthcare rocks!). The biggest difference in my sleep came from when I purchased a machine that auto adjusts based on what you need, so no one could lock me out from getting the best healthcare possible.
I met a sleep study technician who, though convinced he actually has sleep apnea himself, said he could not afford a CPAP. Because he scrapes a living together by working as a temporary contractor for two different local sleep clinics, he does not have health insurance.