Without delving into the rules, it shouldn't matter. AFAIR, for the xONEy fares, it is possible to travel into Nth America, down to Sth America, then back up to Nth America and onwards (if one is a transit).
This link:
http://www.christen.demon.co.uk/CXRule/
has rules ex HKG.
The "circle" to go round world can zig-zag all over the place especially within continents. Eg: SYD-JFK-LAX-LHR is permitted in One World Explorer fares (xONEy).