For narrow mark 50 (!) Euro surcharge in Siegen

Hello, my friend wanted to register her (first) motorcycle in the Siegen-Wittgenstein district today. Unfortunately, you can’t reserve short combinations (SI-X YY or SI-XX Y) online there, but it says there: Quotation: Short license plate combinations (example: SI-A 12) are only allocated by the registration authority. The legislator requires that short license plate combinations can only be assigned for vehicles that do not offer room for larger combinations due to their design. The registration authority decides in individual cases. Therefore, such wishes cannot be taken into account via internet reservation. Now you could easily get a short combination, because hundreds were free. However, the office wanted exactly 50 euros for it! I myself have 3 motorcycles, with us (ST) o.a. short combinations are spent only on motorcycles and can be reserved online. Everything very easy and the 12,80 can I But 50 euros in victories, for what? This will certainly not be more administrative burden, I am really pissed off. Have others experienced this before? Besides, I find nowhere in the federal (?) tariffs for the road traffic office matters such a cost mark. I am quite angry. How should one react now? Many greetings, Thomas