Under federal milk marketing orders, the minimum price a processor must pay for milk used for fluid consumption (Class I milk) is the basic formula price plus the Class I differential. The Class I differential varies by about $3.00 per hundredweight (cwt.) between the Upper Midwest and Southeast Florida. The Class I differential accounts for the costs of transporting milk, the added costs of marketing milk going into fluid milk products, and the higher cost of producing Grade A milk required for fluid products.