A thankless job that takes large chunks of time (corrections must be checked for accuracy, etc.). I wouldn't want to do it, and I don't think you will do it, either.
Many of the songs in the DT were taken from threads and are versions from various singers selected by the poster.
I don't believe that "definiteness" was considered; that would require researching each one.
I raised the question a while back, but I have since realized the magnitude of the problem. I don't like some of the DT entries either. Just make sure that your version of the one true lyric is in a thread.