fuel efficiency

Hi guys, I'm new to this forum. I recently purchased a 2022 Supra 3.0, with only 9000km mileage. I've been driving it for a while, but the fuel economy is around 15.5 mpg, which is surprisingly high. Did anyone have this kind of issue before? I suspect the car has been tuned, but have no idea...

The EPA's FuelEconomy.gov has just listed 2020 Supra 6-cylinder and it gets 24 mpg city, 31 mpg highway and 26 mpg combined! Impressive figures considering the four-cylinder BMW Z4 only gets one more city and highway mpg and two more combined mpg, but down down 80hp / 70 lb-ft compared to the 6...