Hallo Helle,
I had cards similar to yours and found these 6-digit numbers on other documents belonging to the person in question, marked as „DP-Ausw.“
Example Number „024038“, related to Leonids Boze:
- in his DP3 card
- in field 4 in this document
- right column in this document
also see the Arolsen e-guide „DP identity card (IRO)“ (details given with mouse on the different card sections)
So I always ignore these numbers when they are noted down „somewhere“ in the card (like in your example often in the top center. In this case I would leave „reg. number“ blank)
I only enter them in „Registration number“ when the document itself shows them in this field, like in my example above (from this discussion)
I also enter them in (+) destination when a relative is noted with his/her ID number in the field „Remarks“, like
„Wife: XY, [ID number]…“
Let’s wait and see what the Arolsen team will say about this after the holidays.
Until then: have a good time!
[edit]
P.S. Just to seize the opportunity:
What about dates marked as „reg. out“ (registered out) like in this card?
Usually I don’t enter them in „Departure“, but as parts of a free text.
For this card I would enter „died reg. out 29.1.48“ in „(+) destination“. (It says somthing about the persons fate.)
Here „Departure“ and „Destination“ would be empty.
My idea behind it: Leaving a camp and being registered out, this doesn’t have to happen on the same day. (wie „geflüchtet“ und „abgesetzt“ in anderen Dokumenten)
But I am really unsure about this.