Does your exhaust smell as if you are burning Oil? Is there any tail pipe smoke?
You did not say if you were using synthetic Oil or not. Members have claimed that using synthetic Oil freed up piston rings but you needed to drive like 2-300 miles before the effects are noticed.
If your scraper ring and the oil rings are not expanding properly they won't scrap the oil properly off of the cylinder walls and the oil can burn.
Post #20 synthetic Oil frees up Piston rings and gets rid of Blow-by.
http://www.peachparts.com/shopforum/diesel-discussion/323811-best-way-reduce-blowby-15w-40-synthetic-motor-honey-2.html