What's with the funky breathing

[David Clark]

It's been a minute since I've asked about myself and this is mostly a "curiosity" thing. I go to bed around 10 every night and my flow rate starts out with some choppy, obviously awake breathing with some "positional apneas" clustered in some nights...some nights not. Then it transitions into a waxing and waning type breathing that I'm not sure if it's periodic breathing or not. That tends to carry on for a while and then by midnight the flow rate is leveled out and pretty. This is pretty much consistent every single night. 
I'm mostly just wondering what the "waxing and waning" breathing is. Photos attached for each stage I mentioned.