OK, issue solved! Firstly, I updated to the new beta OS and calibrated everything. That completely solved a panning issue I was having (posted in another thread). Once that was done, I came back to this issue. Now when I turn the "Amount" to zero in the amp envelope for the two digital oscillators, the sounds respond perfectly to the velocity adjustments I make in the step sequencer. If I turn the "Amount" back up, it negates the velocity changes I make in the sequencer. So, I'm incredibly happy to have the issue resolved. Now if I can be truly obnoxious and ask somebody to explain WHY it works this way, my brain would be very appreciative! Seriously though, I want to comprehend this.