Yes I wondered about it too. But now look at this video clip fom Sims:
http://www.limbsaver.com/2010/video_center/
Click on "Slow Motion Videos & Tests"
Click on "Archery"
Click on "Dampening Products"
Sims did their tests using a real bow. All manufacturers do things to make their products look the best. But off hand the Sims testing does at least appear more "real world."