I think this is an error by Dan Murphy's but they should have to honour it because it isn't covered in their T&Cs of the black friday promotion.
So there is a list of 779 wines (click on the Black Friday banner) that you can get up to $70 off using the promo code but there is only one individual bottle of wine in that 779 that is on offer at $14.90 reduced from $35.99. However, when you put 9 in your cart it takes the original value to over $300 and when you apply the discount code it thinks that you're spending $300 so it applies the $70 discount.
Edit: I didn't think it worked for bundles of wine on offer (i.e. the Organic Hill Founders Release Shiraz reduced from $300 to $150) but it does if you add one bottle of the pinot in to your cart and also a bundle. It then recognises the original price and applies the discount to that.
It also works for members offers on single wines if you're logged in. So it also works for the Xanadu Reserve Chardonnay 2011 which is on a members offer for $70 from $124.99). If you add 3 to your cart and use the code you get another $70 off.
To top it off shopback have 10% cashback on wines and I used a Woolworths gift card that I got a 5% discount on so all up I'm getting each bottle of Pinot for $6.05.
Edit: the shopback tracked at $30.78 (the original price rather than discounted) but I'm assuming that will be corrected.