On some Android-devices I have noticed problems storing negative values for the new personal-transpose offset. Negative values may be selected from the choice-popup, but get reset to 0 when the song is stored. The problem so far seems isolated to Android 6.x-devices, but I don't have access to enough different devices to be certain this is the problem.
The problem is easily identified by opening any song for edit and try to enter a negative value for personal transpose. Your device is affected if the negative value is saved as a 0 identified when the song is reopened for edit yet another time.
It would be nice if anyone else who experience the same problem could report here, and possibly even submit troubleshooting-info via the help-menu (questionmark) in Bandhelper on the actual device. Ticket number is 22568.
Please look at your help ticket for this. I notified you there of an update in version 3.0.4 that should fix it.
I happened to read this on Sunday, then witnessed the problem on my Android phone yesterday. BH is V4.0 but a -1 Personal Transpose on a song in C# is being ignored. Works correctly on iPad.