yes Larry, that's it, and the actual part (or even voice) assigned is immaterial because you can now reassign it to whatever you like after the merge anyway.

all sequencers are designed for one instrument per track Chuck unless you go in and change instruments within the timeline of that track, thus what you describe is normal for any sequencer, keyboard or pc. But if you have too many instrument changes within many tracks you will end up with timing and/or polyphony issues on cheaper equipment so it is not a good idea anyway.