Mac,
Yes I agree, I saw a gradual increase in fuel economy as I put miles on my truck. But it leveled off during the first 100k. Then I made the changes I mentioned and saw a definite anomaly in my data. This unexpected fuel economy improvement was a nice surprise to go along with the power gain. I guess I could have changed how I drive but it's the same roads I've driven since I took delivery of my truck. My data is only fuel used and miles driven, definitely not enough information to "scientifically" pinpoint the cause of my improvement. I'm definitely a happy camper though!
If my experience is correct, then I could generate even more savings by extending the oil change interval to 7,500 miles. And I do like the 5w capability for cold weather start ups even though I don't live in a cold climate. I always cringe when I have to buy three gallons of Premium Blue Synthetic but my data seems to support a cost savings in the long run.
Dave