I'm looking to book a ticket with AA miles, probably in a few months, for early next year, business class ATL>ICN one way and NRT>ATL back (or vice versa... haven't decided which order we want to go yet). I was figuring that the leg to/from NRT could be on JAL, probably via Chicago, but I noticed that if I tried to book NRT>ATL on Cathay, routing through HKG before Chicago, it was possible to get a layover of roughly 21 hours. Getting one night in Hong Kong would be great, and it seemed like the route fit within the rules of AA tickets.. i.e., this was still the "next flight out", at least on Cathay. This will be my first experience booking complex mileage flights, so question 1 is whether this would even be legal, and question 2 would be whether I'd have to pay the higher mileage rate because HKG is in a different zone than NRT/ICN are in Asia (55K one-way, instead of 50).

Thanks!