The Labor and Benefits component shall be increased or decreased quarterly effective January 1, April 1 , July I and Octob er 1 of each year, commencing April 1, 2010, by the percent change in the indices from January 1, 2010, which indices are specified on Exhibit B, Schedules 1-4. The amount per ton of increase or decrease for this component shall be added to or subtracted from, as the case may be, the amount effective January 1, 2010 of such component, and the resulting amount shall determine the Labor and Benefits component. A calculation is set forth in Exhibit B, Schedules 1-4.