Why don't you look at Jetstar Business Class to Singapore and Beijing with a max bundle. The fares are often very reasonable and you would earn 220 status credits each way.
I'm not sure why but I thought the DSC only applied to Qantas flights and not JQ or OW?
Will need to sit down and look at my options a little later this evening (sadly, I have to do some actual work soon) but will let you guys know what I find