Look closely at the base, it juts out to the south in both renderings. Also the "new" rendering shows a much more constrained north side design, where it is totally possible that the south side remains the same design as the "original" rendering because it faces a more exposed and iconic viewpoint of the skyline. The south side also has an extended wider section the bottom 2/3rds of the building with some form of observation/gathering deck on top of that stepped portion, it would be incredibly unlikely for that feature to be the same on the north side as well- thus making it look like a different building from that angle. The top third of the building looks almost identical structurally besides the window treatments. This is just speculation but it is totally possible both renderings are from the same design.