Bob, I did that this morning.I input C-F-G-C-F-G7 in the key of C. I used all MIDI and what I heard and saw in notation were the chords C-F-G-C-F-G7. I then changed keys and transposed to Am. What I saw and heard was exactly as in the key of C, i.e. chords C-F-G-C-F-G7. There were no chord changes.

Personally I think there are to many variables to transpose from a major key to a minor one or visa-versa. It is not as simple as moving everything up or down a certain amount of steps.

Note that I am using the latest version of BiaB.

I arrived early to a restaurant.
The manager asks, "do you mind waiting a bit?"
I said no.
"Good", he said. "Take these drinks to table 3"

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware