It is a discounted business I fare. Here is the copied text of the fare rules:

Fare rules:Adult: The change fee will be 10% of ticket fare and the refund fee will be 30% of ticket fare before specific time.The change fee will be 20% of ticket fare and the refund fee will be 50% of ticket fare after specific time. Endorsement not allowed.

*specific time:2 hours before take-off

*China Southern shall charge the price difference besides change fee,if there is difference in fare when changing your flight.

I'm sure the same fare class and fare were available for the new date since I purchased a new ticket.

I agree that the 10%/30% is generous for a discounted fare, but my problem is that the fare rules are misleading as they don't mention that the new fare is based on the full fare price.

I usually avoid Ctrip because the fares are often a little higher and then they add a 3% foreign credit card fee. Although in this case, the 3% would have been a better deal.

I won't use Elong because they also add the 3%, but then they sneakily use DCC without giving the option to decline or even informing the customer that they are doing it. The only way I discovered this is because I noticed the charge on my credit card statement seemed higher than it should have been. I contacted my bank and they confirmed that Elong had submitted the charge in USD even though my transaction and receipt were RMB. I was able to do a chargeback for the additional DCC fee, but seems like a pretty unethical way to do business.