I think the problem is basically one where Starrigger doesn't want to add
changes to the css, as it should have been done by Word anyway. I don't know about other authors, but also having worked on his books for formatting, I know that he is very knowledgeable about what he wants in styles.
I also know that if <p> is no indent all the time, (in Word,) the htm commands for the paragraphs add an excessive amount of wording to each and every line when making an htm from the Word docx, which does not
always create a css.
Having to 'fiddle' with css every time you want to create an ebook is time better spent writing the next book, or not having your assistant pull out hair, or roll eyes, etc..
If Word worked better with Calibre, and the codes are right for what he wants to do, it would produce a better ebook for everyone.
BTW: The <p class="center"><span align="center">* * *</span></p>, had to be used for some ebook readers in order to recognize center text at all not so long ago.