Kriegsmarine Sonderbildungsabzeichen?

[Odulf]

Gents,

The enclosed photo came in today, an eBay purchase.

But what a strange collection of badges...

He is wearing (top down):

- Laufbahnabzeichen für Matrose / Bootsmann (blau) [Career badge for Boatswain (blue)]

- Abzeichen für Unteroffizierdiensttuer (blau) [badge for Acting NCO (blue)]

- Sonderausbildungsabzeichen für Schütze / Beobachter Leichte Flakartillerie (rot) [specialty badge: Gunner / Observer light AA guns (red)]

and below these, in the position where regularly a second Sonderausbildungsabzeichen [specialty badge] should be worn the Laufbahnabzeichen für Artillerie-Mechaniker (rot) [Career badge for Artillery Mechanic (blue)].

I have searched through my documentation but I cannot find an explanation why he shoild be wearing two career badges, or why a carer badge is worn in the position of a (second) specialty badge.

Does any of you have an explanation (preferably supported by a Regulation reference)?