Is there any relation between weight class and extreme lifting performance in O-lifting?
I suspect that such might partially result from both an inherent advantage and a coincidental advantage of lower height.  The former would be an effect of strength being roughly proportional to the cross-sectional area of muscle (square of a linear measure) and mass being proportional to the body volume (cube of linear measure).  This would make a 182cm person 10% stronger by body weight than a 200cm person of the same build (when one might initially think that having the same build would imply the same strength per unit weight).

The second advantage might be from taller individuals tending to have a more slender frame.  A more slender frame might be associated with lower muscle bulk (cross-sectional area) even with intensive training (more "ectomorphic"?).  Since there is a limit to thickness, to increase mass height must be increased, and if taller individuals tend to be more slender in build then as mass increases the build would tend to become more slender reducing muscle cross-sectional area (strength) in proportion to mass.