Because Škoda Superb started to sell in january 2002 and 1960s plates were issued only to 31.12.2000. But if the district has 1960s plates supplies it could issued 1960s plates to 31.12.2002. Most of the district ran out of supplies after less than 1 year. ZR ant PT district have very big supplies and they issued 1960s plates to the last day - 31.12.2002 and MB district because it's Škoda's home district and it's normal to see a new Škoda cars even a year before they start to sell (prototypes, test cars etc.)