Thanks for your quick reply.

I have quickly done an online RTW fare ex-ICN:

ICN-HKG-NRT-SIN-LHR-DXB-LHR-LAX-JFK-DFW-YVR-DFW-MIA-JFK-HKG-ICN

and got a fare of 6925400KRW. Taxes (included in this price) were 1796500, meaning they were about 35% of the base fare. Does this sound reasonable?
Is there any way I could get this lower?

Any general comments on the routing would be appreciated as well.

Fraser