Pellet power

So I have a steel target that has 4 hanging paddles that flip up when shot and a big diamond in the middle to reset it after you flip the paddles up. My question is this, when shooting 22cal 25gr Monster RD out of my RW HP at 965fps the paddles get slammed up and it's a very loud slam sound of the pellet striking. When I shoot the FX Impact X 25cal 25gr going 965 fps the paddles get flipped up but at a much more slower speed and less of a report from the impact of the pellet. Why does it clearly appear the 22cal pellet is hitting harder? Both same weight and velocity, physics has me baffled on this one. Target is at 90 yards.