Thank you for the links.
After doing some more tagging and comparing between MJB and Winamp, I've discovered that (today) BOTH are using COMM for Comments, and BOTH are using TCOM for Composer. My apologies on that point. Apparently I can get lost trying to read an ID3 tag in a hex editor.
I see at xiph that a "COMMENT" field is NOT in the list of official ogg fields. But "DESCRIPTION" is, and MJ is using that and giving it the title "Comments", which only leads to confusion (at least mine). If you want to make up your own field names, that's fine; but please, don't take an existing one and call it something else. Why don't you use the field name "COMMENTS" for Comments, since DESCRIPTION is reserved for "A short text description of the contents"? Or, if you want to continue using DESCRIPTION, change the field title display in MJ to "Description"?
Thanks for the reply, and again, sorry for my mistake.