No tonnage displayed?
 

I patroled from Kiel last night, and sank about 70k tons worth. When I RTB'ed to Kiel, my tonnage did not show on the after-mission screen. However, it appears that I did receive renown for my efforts. The ship's log shows that all the ships were sank, but I see no number in the post mission report. A bug perhaps?

A list of my mods:

RUB 1.45
Harbour Traffic for RUB 1.45
Atmospheric Sounds mod
SHIII Internal life mod
Atmosphere Fix 8km LIGHT mod
Hollywood Mod
Merchant Variety pack.

One more while I have your attention. Why is it that sometimes when beginning a new mission the patrol grid says NULL? Is this because you are transferring to a new port?

I had this problem once as well. Just reload at your last save (I always save at the dock before quitting because of this) and quit out again. Your tonnage and rewards should show.

It is a little bug that on your first patrol of a new career, if you buy any upgrades to your sub, you will not see your tonage when you end your first patrol.