What are the best setting for properly formatted conversations?

I love conversations but can’t work out how the software works out what it should display as new in each window and what it shouldn’t. 

I can see there are three dots that you can click on that expand to show the full email but some conversations don’t seem to have the three dots in the right place. It wold be nice if the three dots were always below the signature on every email. Sometimes I see the full email. 

How does the software decide what is new and what isn’t?  In settings I can see that you can change the way an email is indented in a reply and forward! Has anyone any advise on how indent or don’t indent works with conversations or does it make no difference. 

I’ve done some experimenting with this and it seems that you have to have the reply setting set to Indent to have it format the conversations showing only the new content. If some replies to you with Outlook and the settings are set to not Indent it doesn’t cut of at the new only content it shows everything until it finds an indent setting and shows that as new!

If that makes any sense!!