more discussion of this issue here:
Most efficient OW Award ticket request
http://www.flyertalk.com/forum/showt...3&page=1&pp=15

Including examples such as the following:
"You can get fairly creative with the routing. For example, I booked DFW-DEL as part of my RTW, but gave the agent enough restrictions so that the only realistic route was DFW-LAX-HKG-DEL (which I wanted) rather than shorter, and more obvious, routes such as DFW-LHR-DEL.

Result: like the OP stated, it was fairly easy to construct a sub-20k mile OW130C RTW trip, even though actual flown mileage was significantly more than 20k."