I think 827/828 are operating for a shorter period this year. Per ExpertFlyer, the extra LAX-SYD is operating Mon/Thurs/Sat and the extra SYD-LAX on Mon/Wed/Sat. The extra sections start on 15-Dec and the last extra section from LAX is on 17-Jan. IIRC, last year they ran through early Feb, and in 2006 they ran through mid March.

I think it was in 2004 when there were also extra sections SFO-SYD, so there were 3 747s flying US to Australia per day during peak.