> If you do a load 0 does it do the desired 1 -> 0 move?

$ mtx -f /dev/sg4 status
  Storage Changer /dev/sg4:1 Drives, 6 Slots ( 0 Import/Export )
Data Transfer Element 0:Empty
      Storage Element 1:Full 
      Storage Element 2:Full 
      Storage Element 3:Full 
      Storage Element 4:Full 
      Storage Element 5:Full 
      Storage Element 6:Full 

and...

$ mtx -f /dev/sg4 load 0
No source specified

so nope - 

Tom