They aren't illegally exceeding the test, but the dyno testing methods are biased towards small displacement, small turbo motors. Its great for steady state conditions, i.e. cruising down a flat highway, coasting down hill, or sitting at a stop light. As soon as you apply a load, i.e. drive up a hill, accelerate, etc. it consumes more fuel that a properly sized NA motor.
I drive through a small mountain range every day. We never got close to the EPA estimations unless we went on long trips up I-5 where our drive is 95% flat and cruising.
I'm not arguing with you. I'm just saying if it has to perform in Test A well, they are going to do what it takes to make it perform well in Test A.
It's not their fault they are exploiting the limits of the testing method.