Turning back to the codes, they're very interesting indeed, especially because there is at least another occurrence of such kind of codes on a Cant Z 1007 bomber seen in Bresso (Milan) in early 1944 and apparently belonging to the RACSA (Reparto Aereo Collegamento Sottosegretariato Aeronautica) of the A.N.R.
If this "WL+23-xx" pattern is coherent (and usually German things are...), it would mean that there is a type of coding that has escaped us so far...
It would be great to find other examples who could help to explain (or confound even more
) such interesting aspect.