Most Angus and Red Angus have no butt and no bone and that would tend to make the BW a little lighter, we don't breed to them more because a sale barn calf to me is a wasted year, you don't have to breed to a cow killer, but you can make informed choices and get a calf you can be happy with. I do pull some of our calves, but I don't want 60 pound calves, I prefer to breed to a little higher risk Maine and have a calf I have a chance of showing.
The cows/heifers that in my opinion are going to have a problem and need to be pelvic measured are any of the market type heifers that were bred to be steers but you got a heifer and you just can't part with them, those are normally the type you are going to have calving problems on, at least that has been our experience.