Headings tags versus Lists tags for structure

Did I waste my time making tagging changes?

I received a legalese pdf document to make accessible. It was a Word file styled so that almost all paragraphs were headings. Headings 1 and 2 were usually short text and Headings 3 through 6 were typically a paragraph of a few long sentences. I converted the document to pdf and made a few changes (not related to headings) and the file passed both Acrobat's and the PAC 2 accessibility checkers.

Thinking about how a user might navigate through the document headings, I changed the Heading 3 through 6 tags into lists. My reasoning was that it would be easier when navigating headings to just listen to/navigate through the top level shorter text. This was tedious work and now I am not certain it was useful. The multi-nested lists may be harder to follow than if I left the paragraphs styled as headings. The file still passes both checkers.