>>106585450
>Because you are using the default header settings
NOOOOO, you are not fucking understanding it mate! The so-called "Page Style" is baked into the fucking file and preserved in the file even when saving between different office suites. This is all to say that the "default header settings" cease to be relevant the moment I open an existing file.

The issue that LibreOffice's internal maths has NO FUCKING CLUE how to interpret these values. New document, existing document, it makes no difference; they're equally FUCKED.

Do you know what happens if you open a Word document in LibreOffice, notice that the headers are fucked, and then manually change the headers WITHIN LibreOffice? Your document is going to be completely FUCKED when you load it again in Microsoft Office, because now the headers have been overcorrected in the opposite direction.
>there are options in ODT that don't exist in DOCx
What the fuck are you talking about? You can resize headers in Microsoft Office.