Below is a link to a short Youtube Video I uploaded that shows how I repaired a sagging ceiling panel on our 2013 Surveyor Cadet SC-189.
It appears the ceiling panel had basically unglued from the backing. This unit has ducted air. The small buttons were screwed into the aluminum framing.
If you are having sagging ceiling issues, I hope this video will help you out!
https://youtu.be/QP2dSbQDm40