The ceiling vents in your axis/vegas are not unique. The industry does everything pretty much the same. Flow is not distributed evenly.
Here's the deal and the fix.
Remove the vents. If you will notice, the vents protrude into the vent more than the thickness of the vent opening . Cut the circular vent bottom so that it is flush with the inside bottom of the vent duct. You can do this by cutting the vent with a razor knife or blade.
Reinstall and enjoy your new air flow.
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