ORD is higher and qualifies for the fares with a 20% surcharge for exceeding your MPM. It is still cheaper to book a LAS-ORD-NRT routing without stopover and including the 20% than it is to book a ORD-NRT. As soon as you stopover in ORD< though, the rules we are talking about would come into play, and you would not be able to do this without a fare contstruction penalty applying.