Gaucho and Oz:
I received another offer letter prior to the 3-page fancy mailing. This one offers 10K bonuse, 15K and 20K bonus when flying to LAX via Hong KOng(UA resumed this route this year) for economy, business and first, respectively. There is no "first, second flight" requirements. In fact, the letter stated that you could earn up to 60K (by flying first class) by taking 3 flights between 9/1 and 12/15.
The offer is valide for Singapore residents and Singapore point of Sale only. Well, you can always buy the tickets in SIN.