The campus bookstore sells 4,000 sets of graduation regalia each year. Placing an order from their supplier costs $25 regardless of order quantity, so they usually place a large order (a half year's supply) at a time. It costs $5 per year to hold a cap and gown in inventory, primarily insurance costs for the highly flammable material. What is the difference in their holding cost if they order at their optimal order quantity compared to their current policy?