Sounds like you need to engage with Paul Rosen rather than Micheal Eskin then.

You can't mix slurred and non-slurred grace notes in EasyABC either. Or anything else that uses abcm2ps - as, I believe, did the mandolintab.net converter. So it's probably not and issue for most people. Choosing which is an extension to ABC supported by Paul Rosen's code.

I doubt it's an issue for a "new standard" for posting melodies here.