Online agents like ctrip and local travel agents have more or less the same prices. There are exceptions, depending on special relations of some agents to certain airlines, but then the differences are only 5-10% of the ticket price at the most. More important are the changes close to the flight. I have experienced a 50% discount at 11 am on a flight 3 days later was gone down 10% within 2 hours. On the day of flight there were again 30% available.
If you can manage to get 60% you won't get much more anyway. The highest discount I have ever seen on a flight betwenn Shanghai and Shenzhen e.g. was 70%. That happens very rarely. The full price on this sector is 1400.