The customer knew what kind of glass they wanted when they called, then they came to the shop to confirm the glass, and decided to change it. This happens often, as the computer doesn't accurately represent what the panel will look like. Looking at samples, or seeing the glass in another panel can change your mind as to what kind of glass to use. We always suggest you come and actually see the glass in person to make sure you are going to be happy with what you are going to get. The panel was upgraded to an IG unit as well, once seeing the benefits an insulated unit gives over a regular single glaze (uninsulated) unit.