I bought a 2014 XT in Vancouver. Discovered that you can bring it to the states through a great many risky loopholes or temporarily. The TPMS has to be OEM when the car was built. (Can you hear me crying?) I had to sell the Canadian XT and come down to the states and buy an XT w/TPMS. Only solution is own one prior to 2007. The 2015 isn't bad. Although I read horror stories. Hard driving and she didn't eat one drop of oil. CVT behaved as well. I'll probably have the fluids changed. She's just at 60K
Some people on Reddit posted my mpg was really dogfood. I don't disagree. Fully loaded with our crap. Two adults, a dog, a roof rack and a fat suitcase on the roof. It was our undoing. 19.3 mpg is not very good.
That's pretty awful economy. I think your speed was the biggest factor. We did Toronto to Vancouver and back over 3 weeks and averaged 8.8 l/100km (26.73 mpg) in the 2008 Forester (10,000 km trip). Last year, we went to the East coast and back over 2 weeks, just after getting the 2019 Forester, and got an average of 7.1 l/100km (33.13 mpg). That was a 6,100 km trip.
Jeepers! 100K ~ 60mph A much more reasonable speed. As I mentioned we were pretty loaded.
But something is not adding up. I put on new rims Gramlights, wider tires 50x245x18, a stainless steel exhaust, springs (lowered about 25mm) and an anti roll bar 22mm. With nothing in the car I was getting 17.5! I'm not burning oil. I'm using high octaine (91 or 93) gas. With the car loaded I got 19.3. Something....either in calibration of gauges or....heck something else is not computing correctly.
We were fully loaded too with a family of 4. Turbo and low gearing really hurts economy. I don't know what the gearing is like on your Forester but when we took the STi (which has very short gearing) to Florida, we averaged 9.8 l/100km (24 mpg) but again, I was going slowly, 65-70 mph. If I go even slower, 60-65, I usually get around 29-30 mpg. If I go 80 mph, economy drops to around 18 mpg which is about what you were getting.
Yeah, once you start adding "stuff" to the roof (the basket, the suitcase) and then start pushing at 80 MPH or more, your mileage will tank. You're taking the aerodynamics of a brick and making it even worse... Then add in weight (family, luggage, and more) inside and ... well...?
Remember also that the EPA MPG ratings are usually done in a much more forgiving environment - on a set of rollers, speed usually set in the upper 40s to lower 50s for "highway", with limited slow down & speed up situations and even less simulated "hills" ...
Cross country in a real car, you've got traffic, elevation increases (and decreases) and a speed (as noted) above the 50-ish average used for the testing.