I’ve made two trips and admit to trying to drive as if an egg were between the pedal and foot during the second trip.
I also filled up after returning and figured the milage manually as well as the car’s trip computer. 38.5 the first time and 39.1 mpg on the second trip as I attempted to beat the first trip’s milage. I did not go over 70 mph and eased away from the few lights I hit in Mission Viejo. The trip does take me over higher than sea level elevations ( I think 3,000 feet or in that range) both to and from. Look at a map and you’ll see that there are mountains east and north of Riverside on hwy 60 and rolling hills south of riverside on the way to Orange County.
I’m confident I could duplicate that milage easily on any long trip. At a stop for coffee I ran into another Sonata owner who made the same claim on his first long trip.
I am impressed and certainly have no reason to lie. I’m 70 years old and have had lots of new cars in my life and this is the first one to exceed the claimed highway milage.
Truthguy has made several excellent points on this thread, until he decided to engage in name calling.
In your case, I'm not sure how he could know what kind of mileage you got on a trip. I do know that since the early '80s the EPA has revised their methodology three times to, as they said, 'more accurately reflect the real-world results.'
Any person willing to drive reasonably can, for the most part, blow away the EPA ratings. That's because the EPA ratings more than ever factor in those who do not drive reasonably.