Take the wholesale price of the product, add rent, delivery, payment processing, in store labour and all the other expenses involved in running a store, then add 1-2%. That gives you the price you pay in store. That formula hasn't changed since self checkout was introduced, but the cost figures have changed.
I don't see how self-checkout does not come under "all the other expenses involved in running a store". Also, I dont' see how it comes under the 1-2%, which I assume is the profit that the store makes.
I still don't see how all this says that "the cost savings have been passed on to the customer", as per your previous comment.
Take the wholesale price of the product, add rent, delivery, payment processing, in store labour and all the other expenses involved in running a store, then add 1-2%. That gives you the price you pay in store. That formula hasn't changed since self checkout was introduced, but the cost figures have changed.