CMP Classification Card Explanation

I've been out of bullseye shooting for about ten years. I started back up about a year ago and shot a couple local matches then went to Canton and Camp Perry for the Regionals and Nationals. I just received my CMP classification card and there are three entries on the classification card: 
Pistol: Expert w/Ave Score 80
Rimfire Pistol: Expert w/Ave Score 84.5
Match Pistol: Sharpshooter w/Ave score 88.22. 

The Match Pistol classification has a higher score average than the Expert classifications. I'm not even sure what the Match Pistol is. Could I just shoot the Expert class across the board?

Match pistol essentially is 22, CF, and 45 (wadgun) combined.  “Pistol” is really “Service pistol”.  This is why 80 is an “Expert” score while other types of pistol are higher.

I believe it is possible to shoot in a higher than held classification, same as NRA.

Talk with the match director when you sign up. The current CMP rules do not specify if you can elect to shoot in a higher classification (3.11 CMP Pistol 2022 page 29).