During the time I ran Food Lion and before scanning became the norm, we had a policy at Food Lion that once a price was marked on a product at the store level, we never increased that price. If the price declined, we would immediately reduce it. The result was that there were two different prices on merchandise in the shelf, but we educated the customer sufficiently to know what we were doing. It did not take them long to decide to buy extra product of the item at the lower price. This accomplished two purposes: It rotated stock much faster and told the customer we were working for her benefit.
Once scanning became popular, we were not in a position at that time to have two prices on the product, but we did hold up advancing the price for approximately one week to accomplish the same goal. I do not know what Food Lion's policy is now, since I have not been connected with them in an active way for a number of years.