All sub heading levels <i>will</i> appear as a collapsable menu in ADE.
Take a read here. Although It's for CS3, it shows you how to edit you epub files to get the results you need...
https://www.mobileread.com/forums/sho...d.php?t=123439
Basiclly in the TOC.ncx file you can change the order of the toc by changing the </navpoint>s