Shmini atzeres isnt in the next 5 days. Unless its all one holiday, in which case dont mention it. Or maybe its one holiday with 2 names, but that part of holiday isnt within 5 days. It must be that its one holiday with 2 names, but since the 2nd name refers to a holiday that has part of it in the next 5 days, it can be put in parenthesis.