The contactreports will remain the same but the other messages are for sure worth to keep in....
In my last patrol i got several messages between BDU & U-333. Turned out they had torpedoed a German steamer. The back & forth of the message was quite funny and i even thought to myself how that captain was going to be in trouble when he got back to port :rotfl:
Later did some checking via the website uboat.net and later read in that captains bio that this had actually happened
You've got to love those kinda of details in the game.