13.24 A Birmingham, Alabama, foundries produces cast-iron ingots according to a 3-month capacity plan. The cost of labor averages $100 per regular shift hour and $140 per overtime (.T.) hour. Inventory carrying cost is thought to be $4 per labor-hour of inventory carried. There are 50 direct labor-hours of inventory left over from March For the next 3 months demand and capacity (in labor-hours) are as follows: Capacity Month Regular Labor (hours) O.T. Labor (hours) Demand Apr. 2,880 355 3,000 May 2,780 315 2,750 June 2,760 305 2,950 Develop an aggregate plan for the 3-month period using the transportation method