Beyond extreme birth weight calves at both ends of the spectrum causing weak calves from either calving problems or small size another requirement for a calving ease bull frequently forgot about is consistency in birth weight. Where I was at customers generally wanted their birth weights for heifers yo fit into a 90 to 80 LB box. The problems from lighter calves do not stop at calving time. They tend to have reduced performance though their lives resulting in lower profit potential. Bigger calves require higher levels of management making them hard to live to with. If a bull puts out both types of calves it is the worst of both worlds making predictable performance a valued trait.