Most folks do extended OCI's to save money and because they don't want to waste oil. If the idea of extended OCI's catches on, how longer before the oil manufacturers decide to raise prices because they aren't selling as much oil in order to maximize profits? I can see them now "Our old oil cost $2/quart and was good for 3k miles. Now that it's proven good for 7k miles, we'll chare $4/quart.". I can see it happening.