Thanks to the user Thore on the German speaking Ars Gladii forum, I was made aware that the Ringeck manuscript has undergone recent research again. As a matter of fact, the dating had to be re-adjusted to the beginning of the 16th century. Martin Wierschin's impression that put the mansucript into the first half of the 15th century is obviously not correct.
Rainer Welle ("... und wisse das alle höbischeit kompt von deme ringen") had already pointed out by using circumstantial evidence that the Ringeck manuscript has a definitely later origin than the so-called Peter von Danzig manuscript (1452), something that has been widely ignored so far, I believe.
See also this thread.
Best regards
Dierk