Out of curiosity I downloaded that and took a look. Whilst it correctly loaded the tags from a FLAC album (Jon Lord, Deep Purple Concerto for Group and Orchestra) when I deleted the tags and re-tagged it , the program found the right album but it didn't even attempt to set the performer tag (even though it had read it correctly originally).
Therefore, it isn't something I'd recommend for you to use to tag with if you want Orchestra, Conductor, Arranger type roles, which given the classical music bent, is pretty much required I'd have thought.
I'd strongly suggest to give
https://picard.musicbrainz.org/downloads/ a try. The learning curve is a little steeper but it's what is recommended on the Kodi wiki and Kodi is 100% compatible with the tags it stores in files.
I used it to re-tag my album again and now I have my orchestra details back again !! Yay!!