Made It Through Campaign 4, But...?

It took me 23 tries, but I finally made it through Campaign 4! When it was over, my game screen indicated that I had sunk 8 boats, four with torpedoes. When I exited the screen showed that I had sunk 6, three with torpedoes. Am I going crazy?

Congrats. you must have been blind check the log file in c:\....\ert\your_player_name