Here is an article from Creative Pro by Michael Murphy on the use of nested styles. He is a marvelous teacher, so I assume that the article is exceptional. I haven’t read it, because I have written similar things. But you should check it out.
Every book I seem to use nested styles more. The ability to add custom formatting to the beginnings of my paragraphs is too titillating to me. I tend to use this option too much. But it is an amazingly powerful option