I'm wanting to add a particle count test to my Horizon labs UOA to see how well my K&P reusable oil filter did and I'm getting pushback from them and they are reluctant to do it. They said they typically don't do particle count tests on engine oils as the oil is typically too dark for the laser that does the testing to accurately see and measure the particles in the oil. They say that this test is typically done on hydraulic oils or similar "clearer" oils. I have seen numerous people on here post engine oil UOAs with particle counts, and I was told that this is what I need to have done to most accurately measure how well my K&P oil filter is filtering the oil. I am now running a Fram Ultra filter and wanted to run the same OCI and also do a particle count to compare the two. Any thoughts on this?