Hmm, I've never had this problem. If things are moving around and not staying where you put them, try downloading as a PDF instead.
You should only have to format once.
Also worthy of note, don't use the Tab key. It just doesn't work with Kindle.
The only formatting you really need is a Page Break between your chapters and other pages:
Title Page [Page Break] Dedication [Page Break] Foreword [Page Break]Chapter 1 [Page Break] Chapter 2....and so on.
RE: Self-Publishing with ProWebWriter on a $0 Budget - Part 3 - Uploading to Kindle Direct Publishing (KDP) Platform