Extra Class Dates don't generate a lesson plan

I noticed that when you mark a "no-class day" the date drops off the lesson plan section which is great! However...when we add an "extra class day" to the class, the lesson plan doesn't get added. This is bothersome because I would actually like to use that section this year, but if I use that section how I should, then I can't use the extra class days or no-class days section. It seems to be one or the other. What is the point of using something that is going to be inacurate?