Your customer satisfaction percentage shows what percentage of expired items were checked before they truly expired on the shelf.  For a store that checks grocery items 7 days before they expire, the percentage of items that get checked within 6 days of them hitting that list will be added to the positive here.  Everything else that gets checked on or after the expiration date is going to cause the number to go down as it is just adding to the denominator of the fraction.  The higher you can keep this number, the happier your customers are going to be.