Comment 6 for bug 1777667

There is nothing "wrong" in the math, it just behaves unexpected.
if you have a 120 BMP track at 0.5 beat fraction and you seek a 60 BMP track also to 0.5 beat position, the result looks like this:

--|-----------|--- 120 BPM
-----|-----|------ 60 BPM
--------^--------- Phase matches at 0.5% beat fraction