I have never done this Dan but I am interested. What tests do you have Blackstone run and how often?
I get a standard test and add a TBN test. TBN(Total Base Number) is a measure of how much additive is left in the oil. I have had oil that had a TBN of 12 or more when new out of the bucket. Supposedly, newer oils do not need higher TBN due to the clean ULSD and have a lower TBN amount when new. Once the TBN gets down towards, say 2 or 3, it is time to change IF there is nothing else going on in the oil prior to that TBN point.
The last test I had done, including TBN, was about $40.
I run a test every oil change. I suppose I could run a test every other test but I just do a test each oil change.
I started testing with the oil being used per the manual and slowly increased the oil change time per the UOA results. I did not really intend to run the oil longer, I was just curious about the oil and when I saw that the oil was in good shape, I just ran longer.
The standard test is describe here,
Standard Analysis and TBN is discussed here,
Do I Need a TBN?.
Blackstone has some interesting information on oils,
Which Oil to Use?
A few years ago they bought some VERY old oil off of EBay, tested it, then ran it in their engines.
Based on some of the Internet discussions I have read, one would have expected the engine to have run about 2.3 seconds before blowing up.
Some of this oil was in the old containers that one had to push a spout in to use.
Their newsletters are informative as well,
Blackstone Labs
Later,
Dan