Mark,
Again according to UTG, he was initially chosen to command Jasta 29, succeeding
Kurt Wolff, who returned to Jasta 11. Voss took command on 28 June.
He almost immediately took temporary command of Jasta 14, replacing Ernst Fr. von Althaus, who was sent to command Jasta 10. MvR did not keep von Althaus in command long, due to failing eyesight, and he decided Voss was the best choice available to him. Voss took over Jasta 10 on 30 July.
Sorry I didn't post more details before.
Rich