Don’t pay any attention to pages of letters that show up before previous ones have been filled. For example, the March 1942 page where one letter is posted in the middle of the month. I had been working on it when I realized it was misdated. I found its mate in March, with the same incorrect date, but matching paper and a content reference. Both had clear March postmarks. Rather than try to keep it as a draft, it was just easier to create the March page and post it.
Advice: Don’t read letters out of order if you want to read them in order.