If you take the current exchange rate of $1.00 = 1262KRW, then the 8881400 AONE3 fare is a tad over $7,000.00. The $6,083.00 rate on EF is based on the exchange rate of last weeks low for the KRW @ 1460. I don't know who will charge the US$ fare, and if booking through a travel agent in Korea, they'll charge you in KRW.

The taxes seem a bit high, I'd venture it should be closer to 1,000,000KRW.