The Class IV not only prices butter and powder but also affects the Class I mover. The Class I mover (based on "higher of" advanced Class III or Class IV skim milk price) plus the Class I differential for each order determines Class I skim milk price. The mover is equivalent to the Basic Formula Price (BFP) under the old pricing system. It equals (base skim milk price for Class I times 0.965) plus (advanced butterfat pricing factor times 3.5). The Class I mover is announced on or before the 23rd of the previous month.