Always (and I do mean always) gives a wrong bpm value on anything (and I mean anything) I try to load into it, even Rumor Has It by Adele. If I try to examine custom made GarageBand track, the value returned is "nan", which in geekspeak means "not a number", if you were wandering. Free stuff is only good, when it works...
iG.STUDiO about BPM Detector