I have a JD LT160 with a 16hp Kohler Command. I nearing the end of season #2 running Amsoil ASE (typically run about 35-40 hours per year). Last fall when I drained the oil it was still very clean. I'm tempted this year to just change the filter and top off the oil. If I ran more hours I would not hesistate run ASE at least 150 hours. Any thoughts?