2024 IS350 drinking gas? 15mpg on a full tank on eco mode?

I've seen some people claiming they get 20-25+ mpg on their IS350s on some reddit posts. This recent refill I reset my mpg tracking and drove entirely on eco mode. No hard accelerating, tried to always keep it below 2000RPM, 80% city 20% highway, didn't drive much in traffic. Some people even claim better mpg on their IS500s. Could something be wrong with the car, it's still under 10k kilometres.