Djordan,
I am talking here about my little beetle TDI, and not of a fleet. Therefore, it is out of question for me to do oil analysis, as it’d cost me more than buying filter and new oil and get busy for half an hour. I disagree with you that arbitrary oil change is bad, and here is why. It is my own decision when to change the oil, and I do it at least twice a year. The change is not based solely on mileage (around 7,000 miles/year), but rather on season (one change in late spring and another in late fall). After reading post here I was intrigued to try new Amsoil but am discouraged when found out I can get it only by mail(?). So I will be sticking to Castrol 5W-40 for now.