This UOA I did for fun - it's from the Kohler Command SP 15 Horsepower engine on my Toro Proline walk-behind mower, which I believe is a 2004 model. The number of hours are estimated - I could be off by a bit. I am impressed at the TBN retention. Note this oil is filtered, and I am using a Mobil 1 M1-102 as the filter. Looks like it may have sheared slightly. Comments?