I did stub my toes with embedded fonts, with multiple font sizes for special effects (drop caps, dividers)
Kovid very speedily replied with the solution, bless him --- I didn't find the terminology in the interface to be very intuitive (my fault ---
failure to Read The Manual !!!) --- you must DISABLE Font Rescaling.
see this thread
https://www.mobileread.com/forums/sho...d.php?t=264450
So if you have extra-large or extra-small text pieces, check it out.