Tempo doubling on playback

[Tim Mariott]

Sherry
I have now found that the problem does occur consistently in a specific file on both my laptop running Vista and my desktop running Windows 7 Professional (64 bit).
The attached file is an arrangement of a selection of Rogers and Hammerstein tunes.
1. If you start the playback from measure 228, this should be "It might as well be spring" playing at a constant tempo of 75.
2. But when you get to measure 254, the playback suddenly speeds up, though the tempo display and Graph over Notes does not show any change.
3. However when you reach measure 267 there is a tempo change to 120 for the next song.
I cannot be precise about the speed up at measure 254, but it could well be to a tempo of 120.
So my instinct tells me that perhaps the software has read a whole chunk into memory, noted the tempo change but has applied it pre-emptively some 23 measures before it should be applied. Of course without knowing your software I may be completely wrong but that makes more sense to me than a completely random change of tempo.
I have had other songs where this has happened but I have not made a careful note of the details. If this example is not sufficient I will look out for another.
Thanks
Tim