The whole point with shrinkflation is to trick the consumer to think that they’re buying the same amount when they don’t.
If you make it easy for the consumer to see what the cost is per kilogram, they will immediately see that the price for the same size package of cereal they always buy has gone up.
It’s okay if you want to pay extra for your groceries, but I don’t. I’m perfectly fine with compare prices since the compare prices are unaffected by the change of package sizes.