It's great to see a bit of transparency around their pricing games...
Does that website scrape prices from the online shops of ColesWorths? I looked up a dairy free Magnum icecreams (being a treat I buy fairly regularly for my dairy-intolerant wife & son), and it showed a more-or-less constant price for the past two months, and I know I've seen the price fluctuate up and down a lot over that time in my local Woollies (mostly down, when Aldi had some stocked at the same price as the "half price" for Woollies)