Nice Armaband and tinnies, congats.
Maybe I was wrong when I said the A stood for Abzeichen. In the RZM manufacturing-regulations page 17 from 1938 (section Ausrüstung) it was mentioned: red print is for HJ (blue for political leaders and SA).
Further it was said as:
the value for a single tag is indicated by the printed letter, for example
A = 1/2 Pfennig; B = 1 Pfennig; C = 2 pfennig; D = 3 Pfennig; E - 4 Pfennig; F = 5 Pfennig etc. (up through P for 50 Pfennig).
Attached the label of constructor A4/308, made in Coburg City.