Trying to find a way to grab the extended tags that dbPoweramp can create, especially the AccuRip data field, because they will provide unique characters per song that I could then copy over using mp3tag into the comment field. This will provide an easy way for my radio station's logger to easily list and report played songs to record companies and song publishers. The comment field can be filled out with anything arbitrarily, but that is a lot of unnecessary manual work if each file already has something unique in another tag. Generating checksums with another app, I suppose, would also be great, and I could easily copy those with mp3tag.
I've looked in the available options trying to create my own columns and I'm not sure I can pull this off with the available fields and values.
MP3tag has also a function to show extended tags - press Alt-T.
If dbpoweramp writes the extra data into tag fields, they should be displayed in that dialogue.
MP3tag can create an MD5 checksum - when writing an export. This could be imported into more or less any field that you like.
To copy one field into another, see the FAQs: