I've read that he transferred at the end of April on either the 26th or 27th; however, in "Der Rote Kampfflieger," MvR states that later in the day on the 29th (when his father came to visit) both Schäfer and
Kurt Wolff bagged a victory.
Were they just keeping in touch or had he not transferred to command Jasta 28 yet?
EDIT: Either he didn't transfer to Jasta 28 until much later, or he was visiting that day. The very next sentence says "In the afternoon my brother and I accompanied by Schäfer, Festner and Allmenroder flew twice more." So when did Schäfer leave the squadron?