It is my understanding is that the two labs use different methodology for TBN and about a 1.0 variation is expected, their condemnation limit for TBN on used oil is different as well.
It is a long drain oil, in fact if you switch the car to flexible intervals (USA is 10,000) it could go up to something on the order of 18,000 miles (30,000 KM) is what I understand, this is VW dealer oil. Normal Edge is not 508 Approved.