Judging by this interview
http://www.tarrif.net/wwii/interview..._steinhoff.htm and correlating with his claims list in Craig's post above it would seem that Steinhoff went from 10./JG 26 to 4./JG 52 in February 1940 (as he admits in the 6th question) and then to 11(N)./JG 2 for the French Campaign as he mentions in that question that he remained with 4./JG 52 until the French Campaign - but in a later question he answers, when referring to a question about Hans-Joachim Marseille, that he was with 4./JG 52 at the start of the BoB.