Joe, glad you are happy with the HRI's.
I just came back from my first long round trip with them, (2000 miles before the re-balance was resolved) and I did notice a slight drop in fuel mileage from the original Firehawks.
Have you or your wife noticed a difference in fuel mileage at all.
The HRI has the worst rolling resistance rating from the latest Consumer Reports tire ratings, which can affect fuel mileage.
I'm not saying that makes it a bad tire.
My real test with them will be how they do with our Rochester, NY winter weather.

 

Her's replace a set of Dunlops that came stock on it. Seems like here mileage is the same. They actually do pretty well in the snow. This was in NY a couple of years ago.

 

Agree it could be an operator problem, plus once in a while a machine can be temperamental to work with. Still wondering the last time they calibrated it.

 

Friend or not he should know right away. It could keep someone else from having a similar problem, or worse. I'd at least give him the bill from the other tire shop, he can work it all out with them after that. Wether or not you expect him to pay you back.