Very nice Bruce, "mm" block is almost a 20k jump for Spandau in 1916, and the RR is right for them (Spandau receivers 1917-1918 are usually assembled by others). Still, even at this enormous range they are second to Danzig, and not all that close really.
If you take it down one day, let me know the BC and whether it is a sub-contract receiver. It shouldn't be with that RR/1st but you never know, and my database isn't all I would like it to be. Imperial acceptance research is still very limited.