Some (or All?) of the numbers may have been used for after the fact MACRs. As an example, look at MACR 16091.
https://www.fold3.com/image/30087019
Or see images for MACR 16091 starting at page 20 of 27 here:
https://catalog.archives.gov/id/91172417
(Note: the above link starts with MACR 16089 which begins a series of after the fact MACRS. )
MACR 16091 was issued for the crash of B-24D 42-40861 (319th BS) in early 1945 by the 5th Air Force. This plane actually crashed on take-off on 28 November 1943. Originally no MACR was issued. However MACR 16091 notes that there has been a request for details of the crash (often initiated by the parents or the wife of one of the crewmen). So now the Army Air Force Headquarters in Washington D. C. wants "information be furnished to this headquarters similar to that called for in a Missing Air Crew Report, including a list of crew members and their positions in the plane."
Hence MACR 16091 was created after the fact.