I think you're right.

by R. Proffitt Moderator - 12/24/12 6:07 PM

In Reply to: Mp3 time length by pekajo

I recall that the common merge is just that. And you need a better tool.

I see such tools noted at http://stackoverflow.com/questions/10437750/how-to-get-the-real-actual-duration-of-an-mp3-file-vbr-or-cbr-server-side along with why it's only so accurate.
Bob