Your dealer MUST carry VW507.00 due to the requirement of the T-Reg TDI to use it.
VW507.00 is a higher quality base stock thus has better durability when used in extended service intervals. VW507.00 is approved by VW to go as long as 30,000 miles or 50,000 Kilometers between changes when used in conjunction with the oil quality sensor:
Also you should have the system built into the ECU is activated using VAG-Com.
An alternate method is to use a By-pass filter and establish a suitable oil change interval using oil analysis for your type of driving. 15,000 or more miles can easily be achieved in most cases. If you drive mostly highway 20,000+ is possible and still have wear rates at very low levels (>5 ppm fe/1K).
VW507.00/504.00 is also intended for the highest performance engines VW makes including all diesel engines PD and CRI.
DB