This modification allows the product preview to display the same thing that a person visiting your web site will see when they view the product. As written the preview doesn't display the special price that might apply to a product. For a brand new product that you have just entered this doesn't matter since a special price cannot exist for it yet. However, if you are editing a previously entered product then it is entirely possible that the product may have a sale price that applies to it. With this enhancement the preview will now show the sale price just as it will appear to the people browsing your web site.