Luftwaffe Rank of Hauptfeldwebel

[J.A. Twohig]

I am doing some work with the ranks of the Luftwaffe at the end of the war and have some questions about the rank of “Hauptfeldwebel”.
The US War Department Technical Manual TM-E 30-451, “Handbook on German Military Forces”, 15 Mar 1945, Chapter 1, Section 5, Figure 2, “Table of enlisted ranks” lists the following German Basic Ranks and relative US Army Ranks:
Stabsfeldwebel – Master Sergeant
Oberfeldwebel – Technical Sergeant
Feldwebel – Staff Sergeant
Unterfeldwebel – Sergeant
Unteroffizier – Corporal
No reference to “Hauptfeldwebel” is made in the table. However, later in Plate XI, which appears to be taken from JAN 1, it gives the following:
Stabsfeldwebel – Sergeant Major (?)
Hauptfeldwebel – 1st Sergeant
Other references, both printed and on-line, either don’t mention the rank of “Hauptfeldwebel” and/or relate it differently to the rank of Stabsfeldwebel and/or the US rank of Master Sergeant.
I would appreciate it if someone could help me by clearing up the questions of what the rank of Hauptfeldwebel was and how it related to both the other Luftwaffe ratings and those of the USAAC.
Jim