You’d need to test it for a full tank to really know. My lifetime mpg is 29.1 over 9k miles in normal mode. I can’t see sport mode being better since it holds gears longer. My engine runs at 3500 RPM while cruising in sport.
I tested this with my '22 Badlands. In normal mode, I got 20 mpg, eco gave me a little over 21 mpg, and sport hit around 23 mpg. This was on a route that’s 20% city and 80% highway.
It’s weird though. In sport, the RPMs are always above 2000, and the throttle is so much snappier. I’m wondering if there’s a software issue affecting how mpg is calculated in sport mode.