Onkor data update

I won't hassle you with my data EVERY day, but could use a little help understanding this if someone is willing to take a look.

This is my data from last night:

http://www.onkor.net/onkor_plot.html?fi ... 0000000473

And from the night before:

http://www.onkor.net/onkor_plot.html?fi ... 0000000471

The main difference, as far as I can tell, being the AHI as it dropped quite a bit last night. The change I made was to set my minimum pressure from 7.0 to 8.0. Also set a ramp time of 20 minutes. The screen showed the starting pressure would be 6.0, which works for me when I'm falling asleep. I don't think it STARTED at 6.0, though. It felt higher than that. When I pressed the ramp button it did drop. I was expecting it to automatically start at 6.0 then ramp up to 8.0 after 20 mins.

Should I leave everything as is for a few nights?

Also, what I don't understand from the graphs is how events relate to airflow. I can't seem to see any pattern going on, even if I look at a small time period. Am I missing something?