I have a 2014 Ninja 1000. I use Rotella T6 and K&N filters. From 3k miles to 8k miles I didn't need to add any oil, although the sight glass went from the upper to the lower limit. Now, at 9600 and I've added half quart. I've never had a drop of oil on the garage floor and i checked the drain plug and filter for leakage and both are dry. Is this normal?