Nikbear! Paragraphs, please please please!
Back to the topic, then. I don't think the Fog of War explanation works in this case. It's not just that Werner claimed more ships than actually sank - he made claims that his own commander at the time never made.
There are numerous discrepancies, I'm told, between U-Boat claims and Allied records, which is only what one would expect (for all the reasons stated). However, here we're talking about discrepancies between Werner's account and his own commander's account.
On the other hand, I would absolutely expect 20 years to have thoroughly confused dates and places. I would even expect the different patrols to get confused with one another. I worked many summers at a seasonal job where the location and faces changed from year to year, and believe me, it gets to tough to keep track of when you knew whom and where such-and-such an event took place.