Be careful in your sample taking. Don't change your brand of oil after you start your trend analysis. And always send an oil sample of the oil you are using right out of the sealed container as a benchmark for comparisons. I managed a large fleet for 20+ years and used oil testing on both the transmissions and engines. They are just a tool. The fuel delution should be your most important information for potential engine trouble. You would be amazed on how many bearings got wiped out due to leaking injectors.