Although I’ve given up on getting these files (for reasons that have already been mentioned) I will post this information in the hope that someone else will succeed.
At the US national archives, in the NSA transfer group TR-0457-2016-0017, box 45, folder 3953 there is a file titled ‘KOMMANDEUR DER NACHRICHTEN AUFKLARUNG 5, 1944 (S-013,494)’.
It is possible that this file contains the missing NAASt5 reports. Maybe someone can get hold of this file and solve the mystery.