Okay, I understand more now. So no proof yet regarding the meaning of "A12". I understand Wim when he does not give an unequivocal answer as to the meaning of such a designation. I have a large amount of primary literature and documents on the Hitler Youth too and have never read of such a designation for a unit within the Reich HJ/DJ.
The number on the straps of the (Reich) HJ and DJ for the greater majority of the TR was the Bann and Jungbann number respectively (in the early period the Unterbann and
Oberbann were shown on HJ straps but these were deprecated). Nevertheless, within the Reich there was no Jungbann with the number A12 or indeed any other Bann or Jungbann number with an "A" prefix. Oe and B were in existence for a time but both were deprecated as part of the banning of the HJ in Austria and for the B Banne respectively with the latter disappearing in 1936/7.
Banne B and Bann G had specific insignia yes but they were organised in the same way as the rest of the HJ/DJ and BDM/JM i.e into Gefolgschaften (and equivalent) within Bann B or G. In short, I see no grounds for connecting "A12" to units within Banne B and G or any other Reichsbann. There is nothing in the primary literature that I have here that would suggest a link. All we are left with essentially, if we assume that these are DJ or Deutsche Jugend straps, is that "A12" and "I" have some other, as yet, unknown meaning.
The patches that you speak of may or may not be a grouping but we will never know and therefore the other things probably shouldn't be used in determining what "A12" and "I" mean . I'm interested in the "second pattern" RFS insignia. Can you show that please?