I've seen a couple of references here to Motorcraft being 60% synthetic. When did this change take place and how has it been determined? Definitely a great buy if it is 60% synthetic. I had been running Motorcraft bulk 5w20 (three quarts) with two quarts of 5w20 full synthetic. But if Motorcraft is 60% synthetic, I'm wasting money. I can buy bulk for $2.25 per quart.