There is suspicion that Kia fudged this on purpose to achieve their claim of so many models that get over 40mpg in the US. Probably that would be hard to prove.
The variance was only .3mpg, which isn't much, EXCEPT that it's the difference between that claim being valid or not.
However, the credit card for the difference in gas expenses is an excellent public relations idea that, rightly or wrongly, will create more customer loyalty than they will lose through the error.
I doubt Suzuki could be faulted by under reporting mileage claims!
2006 Grand Vitara JLX-L
2009 Ford Escape Hybrid AWD Limited