Interesting points. The oil level drops over night by a quart while the vehicle is sitting. Let me do a deeper dive into the phenomenon.
I drove from North Carolina to my new house in Arkansas while pulling a trailer using the trailer/tow mode as per the owner's manual. This alone would normally result in a bit of oil consumption due to the increased RPMs overall and especially due to the automatic downshifting on inclines and for engine breaking (This, under normal conditions could account for oil consumption for a number of reasons). Over 650 miles of the total distance, I didn't lose a drop of oil. I parked the vehicle, waited half an hour and checked the oil level (I check the oil level every time I stop for fuel anyway) and the oil level was spot on to the full line. In the morning I checked it again and low and behold, it was a quart low. There was no oil under the vehicle nor any on the undercarriage to be found, yet a quart vanished.
I topped the oil off to the full line, drove the vehicle about 30 miles (with the trailer), parked it again at the house, checked the oil and it was spot on full. The next morning it was yet again a quart low. Topped it again and drove about 30 miles on my way back to North Carolina, checked the oil and it was fine. I stopped for lunch, came out and checked it again before setting out and SOB, it was a quart low with no oil on the ground or leaks to be found. I topped the oil, drove the last 600 miles and arrived in North Carolina, checked the oil level and it didn't lose a drop. Drove around for two days (about 100 miles) with no oil loss. Parked the car on the second day in the garage in NC, checked the oil in the morning and SOB, it was a quart low in the morning without any oil under the vehicle or any detectable leaks. A quart of oil simply vanished without any trace or cause while sitting in the garage over night. Topped it in the morning, and two days later checking the oil twice par day, a quart vanished over night while parked. Then another two days without an issue and BAM, a quart vanished over night while the vehicle was sitting, again without any puddles under the vehicle or any signs of a leak anywhere (I used a florescent dye in the oil just to make sure there was no leaks and there were no leaks).
That said, on the big plastic intake snorkel there is a what is tantamount to a catch can near the Helmholtz resonator, but it is dry as a bone.
Just an a diagnostic wild arse guess test about an hour ago, I tried an interesting experiment involving the PCV method used on this particular 6.2L (which has a tube with an orifice on it for the PCV but no PCV valve, per se). I pulled the valve cover with the integral PCV orifice and flushed it out with a proper solvent, replaced the valve cover with a new gasket and something very odd happened - my oil pressure went up by abut 5 to 10 PSI all around. I parked the Puke in the garage and checked the oil level after the oil settled for half an hour and it was spot on full. An hour later, a quart was suddenly gone with no oil on the ground and no leaks whatsoever. The oil seems to vanish while the vehicle is sitting still in the garage. And no one can figure it out because unless there's a glitch in the matrix, the oil is simply vanishing into a black hole (and this was after a 20 mile trip for test purposes). If I was losing a quart of oil out the tailpipe in 20 miles I'd have a cloud of blue smoke behind me that would be visible from outer space.
Unless there is something severely odd about the vapor pressure characteristics of the oil or the laws of physics, there is absolutely no explanation of why this is happening.
