I wouldn't bother with the oil samples, unless you are trying to extend the oil change interval beyond the recommended interval. Then, you can look at the TBN change over several samples and see how it is holding up.

All the metal samples that they report on aren't a comment on your oil, they are a comment on engine wear rates. One sample doesn't tell you anything. Multiple samples can help you establish a baseline for trend analysis, but many people don't bother to get more than one or two samples, and if you change your oil you have to start sampling again, you can't learn much from an interval that includes an oil change.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue