Publisher Tag for MP3 vs FLAC

I have a mix of MP3 and FLAC files. After tagging the Publisher field, some of the music scarpers are not recognizing the 'PUBLISHER' tag for FLAC files.

Apparently MP3 (TPUB) and FLAC (LABEL) have their own tagging formarts and used different field names to stored the publisher information

My question is whether MP3TAG automatically resolves the difference and where exactly does it store this information?

In Tools>Options>Tags>Mapping you can set which (ID3) tags are mapped to which VORBIS COMMENTS.

Thanks appreciate your response it did solve the record label issue.

I have a similar issue with rating the tracks. do you know what is the correct tag name for FLACs that matches POPM

it should be "Rating", AFAICT.
e.g. see this discussion on the kodi forum:
http://forum.kodi.tv/showthread.php?tid=56009

So Perhaps you have to write a routine that adapts the contents according to the FLAC conventions (values from 0 to 100 in steps of 20).