In the Para Style dialog, the font size for Heading 1 and 2 is % but for 3 is pt. The inheritance for all three appears to be the same. How to make it consistent. Release 6.2.4.2
I think you somehow modified the definition of your Heading n paragraph styles.
As shipped, they all inherit from Heading (which, by the way, should never be used for any heading paragraph). Heading defines the font face for all Heading n and the base font size as 14 pt (as opposed to 12 pt in Default Style inherited by all other styles).
Heading n are consistently defined as % sizes so that a single change in Heading updates all Heading n. The built-in relative sizes are, from 1 to 10: 130%, 115%, 101%, 95%, 85%, 85%, 80%, 80%, 75%, 75%. This translates to 18pt, 16pt, 14pt, 13pt, 12pt, 12pt, 11pt, 11pt, 10.5pt, 10.5pt.
Note that Heading 7 to 10 have smaller point size than Text Body (12pt inherited from Default Style) which might be inconsistent, even with bold weight.
The default faces and sizes are set in Tools>Options, LibreOffice Writer>Basic Fonts (Western). The parameter there will be used to initialise Default Style and Heading among others.
You may improve on the consistency by modifying Heading, Font tab and setting font size to 117% (rounded 14/12) so that it becomes dependent on Default Style font size instead of the value set in Tools>Options. But it may be interesting to keep two independent base font sizes customisable in Tools>Options, provided you don’t forget they are independent.
If you want to revert to built-in settings, delete your user profile. Search this site for how-to. After that, you’ll have to customise LO if needed. Chack also your custom templates.
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