To summarize in one place, since the rating in PA is stored as an integer (assuming 0-5 rather than 0-255), and id3 and other tag rating info seems to be stored as a 0-255 byte, any half star ratings will be lost upon rating conversion to PA via Music Playlist Manager app. In essence, this means that while synchronizing ratings to PA is safe (if lossy), synchronizing ratings back out will result in a permanent loss of all half star rating data.
We are assuming the rating integer in PA is stored as a value from 0-5, but it's possible that the rating could actually 0-255 and math converts the value to a 0-5 at the UI stage. This would at least preserve ratings when exporting PA formatted ratings. And while we are at it... it would be great to include functionality for half star ratings in PA too!
@flyingdutchman I'm using tasker intents with the New Music Playlist app to get ratings in PA format in an automated way (COOL!). Really great work on that by the way.
Also, @andrewilley, I'm impressed by how friendly and helpful you are in these forums -- I wish my forums had people like you! Any chance you want to join a math teacher forum? =D