Different environment Hot desert vs cold and rainy. Also, longer distance over a shorter time. Including 1300 plus miles of it being a long drive from another state. A K&N air filter has also been installed a few thousand miles ago. For some reason I did not record the exact date and time the filter was installed. So, combination of a Desert environment, and the KN filter may have caused increased silicon. Wear numbers and insolubles are down though. Viscosity is higher than before. Blackstone, maybe there was actually fuel dilution in the last sample. P66 holds up very well. I still have 3 more oil changes of this oil. It is Dexos Gen 2