Thank You both!

I'm using BIAB 2015.

with the melodist it renders the song with midi styles, then I selected/switched to a real style, then saved or rendered them in mp3 format, and that plays them back just fine.

The problem was when I close the program and reopened later in the same BIAB format/file in order to try the same song with another real style. Everything messes up. the tempo comes in too slow, the parts are jumbled up, even when I try to type the correct tempo in, nothing changes.

I have not used any frozen tracks.