Thanks @OVERKILL
Based on what you are saying, their comments and the "critical" flag can scare the average Joe not having your knowledge. Also not fair to the oil company. You would think they should know better!
The techs that are writing those reports usually aren't educated in engine oils and just have a crash course on the reports. They're often going off a sheet of paper. They run hundreds of samples a day, blitzing them through as fast as they can, and cases with high amounts of ester are likely rare for them. It could be that a piece of paper says something like ">30 - red flag" for oxidation and they go off the paper.
When I send in a sample, I usually include a post-it note on the sample with something like "reference baseline sample #12345678BBQRIBS" but they usually still don't anyway. They likely don't know what they're looking at to even reference it, just still going off the instructions the company gave them. It's like taking a snapshot of a single bit of information with no context. Results get misinterpreted fairly often, but for the vast majority of fleet samples from basic API oil, their guidelines tend to work.
Also, sometimes they're not given all of the information by the customer. The customer may dump a quart bottle of MMO in there, not thinking twice of it, and then when the report comes back showing high fuel dilution (MMO contains alcohol and naphtha), flash point in the toilet, and viscosity diluted out of grade, the customer is sent on a wild goose chase looking for a stuck injector or something when nothing is actually wrong.
There are cases of an oil being undeservingly bashed because of UOA commentary that misread the result. You could have a sample go through with 400 ppm iron, a quick flush before the next sample doesn't get it all, and 10-15 ppm carries over to the next sample giving a higher result than should be. Then the tech flags it. "My wear went up on this oil. This is junk." You also get cases (quite often) where they're running the samples through so fast that cross interference of elements occurs where some of the harmless magnesium detergent or boron EP gets picked up as a wear metal that happened to be right next to it on the spectrum, giving a false result that gets flagged. Unfortunately, it's not perfect, but what do you expect from a $30 analysis. That's why it's good to post results in places like here on BITOG where those us who know what we're looking at can break it down further. There are some companies that do have a tribologist or engineer on hand to review results. Speediagnostix is one such example, but you're going to pay more for their expert input.
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