First letter: The writer should tell friends that she thinks will call not to call, but to expect some people to call that late. Yeah, sucks for her, but that’s sort of become a thing now that everyone has a cell phone.
Second letter: It goes up after Thanksgiving and down before New Year’s.
Let’s see how I did… Miss Manners agrees on the first, but she picked up the fact that the letter writer scolded people on Facebook. Oops.
On the second, basically that.