I am heating 4000 sq ft home with in floor heating and a 1680 sq ft shop with a unit heater. My coal consumption has been about 88lbs a day for Dec. I have the same exact settings as you except I have a KC-10, this is my first year with this unit and I am burning rice coal from a local supplier who gets it shipped in from out eastern Pa somewhere he wont tell me,
... I am not impressed with the ash so I will be trying some other rice coal when I get a chance.
Sounds like once you get your draft dialed in you'll about where you should be. Most people I know with a KA-6 burn 75-90 lbs a day.