Hello, I don't understand the hallmarking on this spoon. There is the assay mark from Christian F. Heise and from Frederik Fabritius. I know that the spoon was made in 1930 by the hallmark with the 3 towers. So Christian F. Heise is correct. But why is there another test mark? Any ideas?
![Image](https://i.postimg.cc/WD35TQgs/IMG-0614.jpg)