That will drop now that he will play the M80s above 95db for hours on end
I was very happy with my own results considering I have worked in very loud environments when younger and never used hearing protection. I consider myself very lucky.
Now that you have 'tested' your hearing, there are those that will suggest those ultrasonic frequencies do add to the 'feeling' of the music/sound akin to the subsonic subwoofer notes you don't hear but feel. I have had one occasion to listen to a super tweeter set up and I found it didn't add anything, YMMV.