The same conclusion I came to after checking many sources. There is the line:

"Er starb 1792 als österreichischer Feldmarschall und Regimentschef."

Perhaps the later part is as

Regimentschef Infanterieregiment Nr. 39 in preußischen Diensten?

I note several sources state that he returned to being a 'Regimentschef' after the SYW.