Similar to my oil analysis after a 7.700 mile interval and mostly street driving. Except my iron was only 11ppm. Silicon was 19ppm. My next oil change was at 8k and had elevated levels of wear metals due to a lot of autocrossing, but not to extreme levels.
My new interval is 5,000 miles during autocross season and 8,000 miles otherwise. This is using 0W40 Mobil 1.
15,000 mile oil changes? Yeah right... if you want the motor to wear out in 100,000 miles.
