Why is that surprising?... Your own tests showed it was more accurate, had lower felt recoil and probably was less stressful on the gun as well.
450 FPS is more than adequate for a target pistol and the 33 FPS lost will not be noticeable at all, but the other effects were.
Power is not everything and sometimes less is more

Interesting results though and thanks for sharing them

BTW what differences were there, if any, on cocking effort?