Ha, I just went on supply mission, then got orders to patrol luzon straits and sunk a 1800 ton ship. I then got orders to patrol china sea and got a destroyer. What did I get when I got back home? The silver star
for under a 3000 ton patrol and landing supplies.
I guess I could write it off as being December 1941 and the brass was eager to reward any success they could find and that I'm playing at 100%. What difficulty are you playing on? If it's not 100, you won't get full renown credit for accomplishing goals and sinkings.