At one point, the standard CSM800 80K J awards had a 21-day advance purchase requirement and you could only get 110K or higher awards in most markets less than 21-days out due to that fare rule. However, there was a subset of markets where there were also 80K awards that required purchase less than 3 days out. They appear to have done away with all of these and most markets do not have any advance purchase requirement on the CSM800 80K J awards. There's an exception for PEK and PVG in that all awards (not just the CSM800's) now have a 3-day advance purchase requirement. Other markets outside of these (HKG, NRT, ICN, etc.), do not have the 3-day advance requirement in the fare rules.