For fuel mileage and EPA testing ratings, I suspect that partial throttle settings would not cause significant shift changes. I do also expect that this completely new car should most certainly have the new 10-speed transmission, which means that it probably did downshift at least one gear, but they are close-ratio enough that you didn't really notice. He clearly was not WOT at all.
to me it sounds sick, but turn up your volume and listen, I think it downshifted very quick and revved thus the noise it makes , if was in whatever high gear it has then I don't think it would sound like that and just be kinda quiet like it is while it was cruising along. whatever, I can't get excited over that car.