It seems that BB doesn't express the same resolution as ACW when bringing in a song that was anolized by the ACW.
The tempo of ACW has a higher resolution/fractions/decimal point accuracy, so when importing the anolized song, it screws it up because it can't see fractions/decimal points as accurately as portrayed by the ACW's tempo decimal pointed tempo.
It tries to follow by changing the tempo quickly...and this causes rather bad transitions between bars and beats.

I see that Real band uses powertracks audio and ACW...I believe power tracks audio has a better tempo resolution...one more in line with ACW...so less confusion when importing the song from ACW.

What I would like to see is BB using that same resolution in the tempo...so that the ACW can be used with greator success!

Just one of my wishes...It would make the hole package worth while.

Sir Les