thanks again Hatzie, that's good info
I like the 5K interval/multiple approach - I do wish the factory made a simple chart in the owners manuals - the goofy way they spell it out at each weird interval seems more confusing to me, so I make my own chart. I'd say most of us on this site are light years ahead of the rest of the general public for being pretty picky about our PM, ha. I'm probably too picky, but I'm ok with that.