That was just a simple test to see if Mp3tag can create tag-fields or not.
Search the forum for "rating" und you will find a bunch of postings.
Once I did a test for RATING MM ...
Rating and mp3tag/MediaMonkey sync problem
... but in the meantime there might happened changes on the MM side regarding the decimal values in relation to the rating classes.
DD.20150122.2046.CET