Since you're already ticketed, it sounds like you're seeing an offer to buy up to Premium Economy for 281,300 miles for one direction. That tracks since, if I were to try to buy those exact flights for points right now as a new booking it would be a lot more. Your friend may or may not be aware that AA now prices awards dynamically, whether it's for an upgrade or a new ticket.. There's no longer a fixed rate. They charge what the demand dictates.
Keep checking your reservation as the dates gets closer. If they have unsold seats they may start reducing that offer and you may also see business class awards. The first row is showing Coach/PE/Business. The LAX-SYD/SYD-LAX legs have a First class cabin as well and it shows up on the return search.