As per Doweyy's suggestion here:
https://www.ozbargain.com.au/node/461740#comment-7359241
Only a good price if you saved the Amex Offer down.
Worth noting - with the exception of the TGG Commercial deal, they have never been this cheap!
Also worth noting there is speculation that Sony is charging their suppliers more as a result of the popularity of the headphones, meaning the days of $320 eBay deals are likely few and far between.
Use live chat (closes at 10pm AEST) on Harvey Norman's website and use TGG's $395 less 10% off ($355.5) as a price match.
Note you can try your luck getting black headphones but my live chat guy would only price match on the Silver (TGG website only has silver).
Good luck!
10pm UPDATE: HN Live Chat closed, TGG deal still available until midnight.
Sorry, misread the post. Delete!