Voicing in Key editor vs Score Editor

In example below I had to change the voicing of the bass note to voice 3 or 4 based on the score settings.

But in Score editor we can change the voicing to Voice 1,2 or 5 and 6.

  1. Why are the voicings in the Key editor different from those in the Chord editor?
  1. why do we have two sets of voicings?
  2. Why aren’t we able to assign voices 3, 4, 7, or 8?