wow thats a big mower. But didnt you say he cuts his grass every week? I would not think that it should pull it down to bad. Those blades are sharp and grass is short.
I can easily see how my 4 ft bushhog with blunt edges beating the grass down thats 5 feet tall wet festcue would be more taking than that running over a lawn. or by hog in blackberries and little trees, both of which a 4 fter is all the 2000 wants.