B&M uses very round and concise pullups
I'm not sure what you mean by this Xpress. If you mean that the bottoms of the hills have a similar radius throughout then have a look at the more modern hypers. Yes some of the older ones have quite a rounded bottom, but take Intimidator's first drop for example. It flattens out a little at the bottom, I assume this is the same reason why the hills appear to have a small point at the top of them.
Instead of having the highest point of force right at the lowest point (which would create that round shape) the newer B&Ms grab the higher force early on and then maintain it across the bottom. Obviously the trains speed increases so to maintain a constant force, the radius increases slightly to make it level off a little at the bottom.
Hope that makes sense =/. But it's something I noticed when doing my hyper. It's only subtle but hey.