I am just on an F RTW with a similar routing (HND-FRA-JNB-ZRH-STR-FRA-LAX-PEK-HKG-BKK-HND).
I am also going back from BKK to TYO. In my experience you can do anything inside each of the 3 areas (in this case Asia/Australia...) as long as you don't exceed the maximum mileage, don't stop twice in one city and don't go thru the starting point to somewhere else at the end.
There are more rules, but I tend to believe your original itinerary should work.