Roy,
For AOD, I am only upto the end of 1940. And I admit to reloading once from a save game to bring my sub back from the dead.
Recently, I have started playing the included/download scenarios for AOD and SH1. Originally, I skipped them, but I am learning a lot from them.
Also, I cycle through games and at the moment I am investing some time with SC and staring at BB and NB sonar tracks.