Thats pretty odd the guy took so much time to do the testing, but failed to match "reported" Micron and Efficiency numbers vs. what he actually found.blythkd1, you may be more interested in this study instead of the "study" done on this forum. I've referenced it many times, and every time it gets glossed over as something of value because people would rather argue their opinion than look at actual results.
This is what I took away from it. The VERY BEST filter tested was the Royal Purple filter. ( Reported to be made by Donaldson) It's the top of the heap, as far as consumer grade filters are concerned. Here's the test results.
This is a 25 micron, 99% efficient filter.
Compare this to the Donaldson DBL7483. 15 micron , 99% efficiency ( 10 micron at 90% !)
At 99%, the Donaldson is clearly the better filter with a 10 micron advantage. Other factors such as cost and expected time in service played into it as well.
Consumer filters cannot compete with it, on any level.