I'm not twisting history to suit SH3, just pointing out that calling the singel merchant map contact unhistoric is not correct. The level of frequency is up to debate, as is much else. I could just turn around the question and say that you provide evidence of the oposit.
I've not found the page and it might be on a diffrent page in my version since its an extended swedish language edition I have. It's 5 books instead of 2 and lots of info about swedish ships hit by uboats, extra drawings, maps and pictures etc.
I'll keep looking though when I get time away from the political geography books I have to read.