Maybe SBS4xxxx is reserved for Citaros.
While there is no such rego as SBS 4Z.
1Z, 2X, 3T, 4R, 5M, 6K, 7H, 8E, 9C, 10Y
They need so many regos for citaro meh? They have 6900 - 7299 to
use now leh... then wright use 4xxx series so rego is in order
mah...