A "half way" victory for the manual bass problem Audya4 for accordion.
After checking all of the suggested settings which were all fine, I changed BsonStop to BsOFFstop (3/8). This allowed manual vs arranger bass to activate.

And although the bass voices can be changed, the volume parameter does not function (manual mode only). Adjustments of bass volume parameters from low to high (including 0) the bass sound is constant in manual mode. A loud "flat" bass sound. I am using the bass volume slider to over ride the problem right now, but it should work like all other parameters. To change the bass octave, I must come out of the "view" window and go through 3-4 additional windows in order to manipulate the bass octave. A lot of steps. Any suggestions?

Thank you Joe & Gary for your helpful support and interest. It's very much appreciated!