Looks like you nailed it. I believe your are correct with the fiefdom part as well, I stumbled on that one wondering if it might have been the same “F” symbol you might see in the word leftentant, or to represent an “s” like you might see in early Congressional documents where they show as “Congreffs”. It looks like these ‘f’s were actually f’s for a change. Your translation for revenues was dead on too, I was able to find it in an old Chaucer book. I am still hunting around trying find ‘sorertreu’.
Is ‘sorertreu’ just ‘so rare true’ ?