2: Thomas uses Isacsson on the site, because it looks more "Statesider " and the majority of his users do come from the USA, but his legal name is spelled Isaksson. And yaknow, that was such a professional letter, he'd want to make sure to sign it with his 100% legal name.
That's most likely. I found a
cached google page which refers to "Jan Isaakson" as a personal reference from TSR.
FYI - all of my PayPal receipts for my (now-canceled) subscription were to "AB Jan Isacsson".