so you done a bit more digging and realised your first line was wrong as he was only provisionally given it provided he passed the criteria which he never didThe US Army's official newspaper says he was a command sergeant major btw. I'm going to trust them to get that stuff right.
Apparently he reverted to a lower rank at retirement as he hadn't been in grade long enough to cover all the promotion paperwork and qualifications. Typical army *******s.