We've had cars in stop and go driving that are burning about a quart/1k miles get set to a driver that does long trips and the pattern is that the oil consumption tapers down. I looked in the database today and the down turn was about 50% in the 8 cars I looked at. These cars were all on Motorcraft 5w-20 with over 30k miles on the clock, doing 5-7.5k intervals. I don't know if this means anything except that these engines like longer trips is less consumption is better.