Quite a nice big new missile NK has there. Looking at the design it does not look like it would have much, if any, additional range over its predecessors. There is quite a bit more structure and weight around the missile bus and the upper crutching point is quite a bit lower than the bus reinforcement. The extra girth also necessitates addition structure and weight over the narrow-body design. Nobody adds a gramme in that area without a very good reason; it just eats away at performance and you burn fuel just to carry more fuel.
My guess... here comes MIRV, with a subtle hint of Chevaline.