AC vents modification

We recently traded campers and I noticed that the AC vents in the ceiling stuck into the ductwork a little over 1".


I removed a vent and noticed the space between the ceiling and the bottom of the ductwork


I used duct tape to seal the area to prevent any cool air from being lost into the attic space.



I cut the vents down by about 1"



Then reistalled the vents.


I didn't have anything to measure the airflow before or after, but, with just my hand it did feel as if there was better airflow.