Good advice from the YR and a good move on your own behalf IMO. If you were close by, I’d tell you to stop over and I’d hand you the tools. Throw it up on my bench and have a look.
That’s what I did for my buddy with the ProMaxx heads. I took two valve out and did the free flow testing for him. Then I recommended for him to take each valve out and we would check them over together. He wasn’t interested so after we flow tested them he was on his way home. Ohhhh well.