Cpap with oxygen requirement

Hello, I a cpap user since 2012. I recently had a sleep study and my machine is to be set from 14 down to 9. I have a list of health issues, but the heart failure and low output or low EF of 24% is new since 2012. I know have a internal deffribular. My sp02 was 88% with the pressure of 8. No ahi where recorded but at setting 9 my 02 went to 89% but .6 ahi was introduced. I am perplexed at the results. I think I need supplemental 02. Does anyone know if the rule for medicare which is online. My study states the results where broken down as a report would be, the statement was my 02 was @ 77% for 12 minutes. I can't figure out using the medicare rule as it says with cpap sp02 is 89% or lower AND for 5 minutes or more. What I don't get is do they mean when my 02 was at 89% machine set to 9. I also had to have a drop in 02 for 5 minutes while titrated at 9. Or when tested 9 was the best setting I am at 89% 02 and the study showed me having ca and osa that lasted 12 minutes which is the secondary requirement. My 02 when sitting is 92. But I am around 94% walking around. I'm 48 years old my index is 21. I have had 2 heart attacks and a triple bypass. Now congestive heart failure. I'm sure the thought is ask your doctor. To make it simple I have not seen my pulmonary Dr yet? One of my other drs ordered the study as my insurance changed so me visit was 3 months out or behind. Lucky me lung doctor canceled and now I wait two months but have a study. Found that 02 has to be ordered at time of study. That was 5 months ago. So the odd thing is the Dr who read the study with out seeing me has no idea about heart issue. And he quit the hospital so can't see him. So that's why I wanted a opinion as I don't have copd. My hands are tied with my insurance. My doctors are not willing to go into the details of the study as they want the sleep doctor to do his exam so what I asked above I can't find out. I will take info as opinion as I understand medical advice is to be obtained from a Dr. Thank you Troy.