Oil consumption too high

I am also wondering if I should pursue a warranty claim for excessive oil consumption. I had the oil changed by Subaru prior to leaving on a cross country trip (3,000 miles). Sustained speeds were 70 to 80 MPH and there were plenty of steep grades along the way. I brought along two quarts of Mobil1 because on two previous coast to coast round trips, the Forester consumed one quart in 3,000 miles. On this trip I had to add one quart at 2,000 miles and I see that the oil is halfway between the marks on the dipstick at 3,000 miles. The odometer is only at 51,000 miles. Interesting to note that before a 3,800 return trip, I did an oil change using Valvoline and a factory filter. Only a half quart was consumed. Also worth noting is that oil consumption is only a problem when sustained speeds are over 65 MPH. Otherwise, I don’t see noticeable consumption for normal day to day driving around town and round trips of 120 miles or less at freeway speeds of 65 MPH. Valvoline seems to be the one brand that burns less and Mobil1 the most. The only other brand used was Chevron that the dealer used initially, now Subaru Oil. I have used Valvoline exclusively in my two Sprinter RV chassis with exceptional results. Mercedes-Benz is very specific when it comes to engine oil.

Last April, I got a new 2017 Subaru BRZ and this September I got a 2019 Subaru Ascent. My intention is to pass the Forester on to my daughter to replace her well worn Mazda. It makes sense to keep a low mileage Subaru in the family, especially since the extended warranty goes to 70,000 miles and to year 2020. I understand that Subaru is not alone when it comes to excessive consumption of low viscosity oil. The Forester engine performs well in all other respects. I have been told that once the oil consumption is noted, it will only get worse... a lot worse. I don’t see a quart or two between oil changes enough reason to tear apart an otherwise good engine. A major repair is pretty intrusive and could be the start of other problems. Sort of like elective surgery to correct a condition that could be lived with to avoid surgical complications. What I don’t find acceptable is having to add a quart of oil after every other fuel fill up. Is that what we can expect going forward to the end of the useful life of the engine? Then maybe is would be wise to have Subaru do something now. One thing that may complicate an oil consumption test is that negligible amounts of oil is burned with normal driving. I am certainly not going to drive back to the testing dealer 2 1/2 quarts down just to prove a point.