I recently decided to spend some cash on oil analysis for my "S" and my Toyota pickup. I spent a shade under $200US on a pre-paid analysis kit from Blackstone Labs. The kit included 6 pre-paid samples, the pump ($25), and the TBN at $10 extra per sample. The 6 sample bottles arrived via UPS a few days later with no pump and no postage. I immediately emailed Blackstone to correct this problem. Kristin replied quickly and sent me the postage and pump. No harm, no foul. Stuff happens. As a courtesy, I sent her an email describing my concerns about Blackstone's quality control procedures and made a recommendation that Blackstone take a quick look at how they ensure that the sample analyses are actually correlated with the correct customer. In other words, make sure that the oil analysis is actually reported to the correct customer and not reported to another customer ......giving a false report. In this case, 2 customers would have erroneous analyses. Evidently, my suggestion fell on deaf ears. When Blackstone reported back to me on my analysis, there was no mention of the TBN($10 extra). When I emailed Blackstone about this omission, suddenly I have an amended analysis with the TBN recommendation. Did they keep my sample and run the TBN days later? How reliable is this TBN sample now? After I expressed my concerns about their sample integrity, this problem manifests itself. I've lost faith with Blackstone and will email them about my concerns as soon as I finish this post. Perhaps Blackstone is a high-quality lab. I don't know, but my own experience is of a lab in disarray with sloppy controls. Any lab worth its merit has strict controls for sample integrity. Blackstone has shown me that they are haphazard.