Hi Cad
Well, it looks at the Backtiming Column from what I could tell. As a test, I ran it on my playlist was told that it couldn't trim 138 seconds. So I put a StartNext marker about halfway through "Whole of the Moon" by the Waterboys, it then said it couldn't trim 84 seconds. So, by my reckoning - it's calculating total playlist time using the Backtiming Column.
As for the Control Bar duration display - I suppose it's a good way of seeing how long a playlist "could be" were it not for StartNext markers and cheeky scripts that do all sorts to the timing of a playlist
