I had the same issue on an 03, it turned out to be the injectors... I did the orings first, but no change. Sent the injectors to be tested and wound up being them.
In a weeks time, say 150-200 miles, it put 1-1.5 gallons of fuel In the pan. No smoke.
Good luck with it.
That particual high pressure pump will produce a performance complaint before it puts fuel in the oil by its architecture.
-Check the fuel return line restriction, Max of 4"hg
-If with in spec. remove valve cover and run the engine from a bucket of dyed fuel, viewing with a black light and monitor. Some times your need to load the engine to reproduce the complaint.
I've also had injector bodys leak themself. O-rings are cheep, replace the coppers also.
Ok, here is an update. Turns out the motor is a mechanical model ( I believe) . The inj's dont have a solenoid pack on them . The Inj's are narrow , about 1" diameter and 6-7" long. The only thing that seals them is a copper washer and maybe some type of jacket instead of an O ring. I dont believe the inj's are sealed well, so it must be another issue besides O rings.