This SN+ oil was in service fifteen months. Oil filter: K&N HP-7035. The K&N air filter (part number 33-5075) was installed at 18,059 miles. The vehicle is operated in a hot and dusty environment (Phoenix, Arizona). With this oil sample I am trying to determine if my choice of PUP 10W-30 and K&N filters is adequate for a 7500 miles OCI. I doubt I will go with Blackstone's recommendation of 9000 miles on the next oil change interval because I want to maintain the warranty requirement. I am glad, however, to see such good wear and TBN numbers and will probably stick with this combination throughout the warranty period.