Gas mileage low?

I own a 17 Camaro 4cyl rs and was getting low numbers on the Chevy app, the car is advertised around 22ish mpg and has 17 gallons therefore it should be well over 300 miles, I also drive in tour mode mostly all the time and no hard/harsh acceleration. Any reason why it is this low or is it just the app?

I own a 17 Camaro 4cyl rs and was getting low numbers on the Chevy app, the car is advertised around 22ish mpg and has 17 gallons therefore it should be well over 300 miles, I also drive in tour mode mostly all the time and no hard/harsh acceleration. Any reason why it is this low or is it just the app?