Right, basically you "point" out of the 250 class. Like what happened with Brock Tickle a couple of years ago. And there are riders that ride both classes; Vince Freise rode 450's in the west and is on an 250 in the east coast series.
Makes for more exciting racing with the fast 250 guys are on 350's or 450's. KR got a 2nd last year on the 350 and Cole Seely had some impressive rides on the 450.
Besides Geico has to do something with their 450 besides pre race transfer jumps.