murph, a hard 90 would cause problems with the air flow... air doesn't like to do sharp 90 degree bends, if you were to put a 90 in there it would greatly reduce the CFM rating of his HVAC system... this is probably the reason for the custom part, maintain the CFM rating with non-standard parts... you will need the same overall volume inside the duct, with a non-standard shape....
I believe this is the reason for the "custom" work...
Yes, that's why I mentioned it might be the deflector driving it up. Still, I ran this scenario, pics and all, over the guy fixing the bathroom fan button hooked to our air exchange system last night and his advice was, rough quote...
"I won't criticism another professionals pricing but your friend would be smart to get two or three other quotes before settling on the job."
Hope you don't me checking with him. Just trying to be helpful.
