[Merlin]

Ed,

all A 48 aircraft, which received a four letter civil registration were in the D-I class. This aircraft was too heavy for a D-E registration.

Norbert,

I have a photo copy of this Ar 66C from Sch./FAR 11 at Schönwalde during 1940. It shows clearly the number 410 in white at the fuselage below the wing and the registration PJ+A? (unfortunately the last letter is hidden behind the wing).
I'm afraid you have to check your source for WNr. 410 = ND+NX again.