JFK-LAX was my only transcon. My actual NA segments were:
DFW-ANC-DFW
DFW-SJU-DFW
LAX-JFK (QF 107)
though my transcon was done as part of my 'transit' from South America to Australia according to the rule above. QF 107 LAX-JFK was a special case, usually QF does not have rights to sell seats on this route, but it is useable as part of a RTW.