Received my MS P100D in December 2017. Cruise/autopilot wasn't available for about 30 - 50 miles or so but then kicked in. I had never heard of someone needing 500 - 1000 miles for it to calibrate. That just doesn't sound right. Most I have seen say about 50 miles.
Are there a lack of lane markings in your area or something? Could that be a reason why it would take longer?