If it's 30% less waste doesn't that directly translate to more profit? Unless they flat out ordered 30% less stock. Which is still more profit?
I hate economics.
I am all up for minimising food waste though, so if it's this effective then maybe it is a good thing. Apply it to all areas of supermarket shopping?
I'm presuming the less waste comes from knowing how much stock has been put out, and how much has sold so if there is excess stock left, the price reduces accordingly to make sure they sell out preventing waste