There is no permutation that allows travel to/from the SWP on an xONE3. Even if you don't get off the plane in Asia you still have to count it as a continent, hence N. America (1) SWP (2) Asia (3) Europe (4.) Same goes for Africa and South America itineraries - can't be done on a 3-continent routing. The exception to which you refer is to the prohibition of re-entering a continent, thus pax going, say, XXX-HKG-SYD-(SIN)-LHR are allowed to pass through Asia a second time as long as it's one flight no. with no stopover. But if the wheels touch a continent, the continent counts.