Questions about the car tax

Hello everybody, I hope I have caught the most appropriate forum – if not please postpone. It’s about the question whether the car tax really goes after the first registration day or maybe there are exceptions. I drive a 330D convertible with EZ 28.10.2008. Accordingly, the space-based tax rate of 15.44 € is charged to me. If the vehicle had been registered a week later, I would only pay 369€/year instead of 463€/year. (Source: tax rate.de “Vehicle holders, who have registered their car in the period from 05.11.2008 to 30.06.2009, can also benefit from the new tax”) The vehicle has the facelift engine (N57) with Euro 5 and DPF ex factory as well as the vehicles in the following years, so it is purely about the date. That there are deadlines here is clear to me, however annoying that is. My question is now whether the “date to K”, i.e. EC type-approval in the vehicle certificate plays a role. the 22.01.2009 dated (comfortably after first registration). For the EC type-approval relevant pollutant class (row V.9) is the 715/2007*692/2008A. For every hint I would be grateful. It would not be the first time that the competent authority is mistaken and ask for nothing. Greetings and a nice Sunday still.