I've already started my RTW days ago with CAI-AMM-DOH & DOH-KIX. When I chated to Qantas to change my ticket on Twitter, the agent told me the flight I want to add exceeded the limit.
For the fare that you have, you can have 4 stopovers in Asia. With the new flights you are wanting to add: KIX-HKGHKG-KULKUL-CANCAN-HNDHND-DFW You are stopping in 5 different citites, where you are able to have 4 stopovers. If we remove the CAN-HND, that means you are within the allowance of the ticket.
I checked the rules, no words limited the stopovers in continent but limited the segments in continent. Since DOH-KIX & HND-DFW is intercontinental flight, I suppose KIX-HKG-KUL-CAN-HND can satisfied with the rules, right?