This is my last suggestion for today I swear There are sections for a synopsis and writer guidelines in the current story format. I would like to put forward the idea of an optional dedicated author notes section. A lot of stories currently have chapters with such notes simply labeled "Author Notes". These sections are not really chapters and might benefit from just another textbox somewhere. I think the proof is in the pudding though and asking other authors if they would use this in place of a chapter might tell you whether it was really a good idea or not.
