eveything is correct except for one cell and i cant figure out why??

Develop a production plan and calculate the annual cost for a firm whose demand forecast is: fall, 10,500; winter. 8,400; spring. 6,800, summer, 12,000. Inventory at the beginning of fall is 525 units. At the beglhning of fall you currently have 35 workers, but you plan to hire temporary workers at the beginning of summer and lay them off at the end of summer. In addition, you have negotiated with the union an option to use the regular workforce on overtime during winter or spring if overtime is necessary to prevent stock outs at the end of those quarters. Overtime is not available during the fall. Relevant costs are hiring. $90 for each temp: layoff, $180 for each worker laid off, inventory holding, $5 per unit-quarter, backorder $10 per unit; regular time, $5 per hour, overtime $8 per hour Assume that the productivity is 0.5 unit per worker hour, with eight hours per day and 60 days per season. In each quarter, produce to the full output of your regular workforce, even if that results in excess production. In Winter and Spring, use overtime only if needed to meet the production required in that quarter. Do not use overtime to build excess inventory in prior seasons expressly for the purpose of reducing the number of temp workers in Summer (Leave the cells blank, whenever zero (O) is required. Negative values should be indicated by a minus sign. Round up "Number of temp workers, Workers hired and Workers taid off to the next whole number and all other answers to the nearest whole number.) Answer is complete and correct. Fall 10,500 525 9.975 19,950 16,800 Summer 12,000 1,600 10.400 20.800 16,800 0 Forecast Beginning inventory Production required Production hours required Production hours available Overtime hours Tomp workers Temp worker hours available Total hours available Actual production Ending Inventory Workers hired Workors laid of Winter 8,400 -1,575 9,975 19,950 16,800 3.150 0 0 19.950 9,975 O 0 0 9 Spring 5,800 0 6,800 13.600 16.800 0 0 O 16.800 8.400 1.600 o O OO OOOOOOOOO 0 16.800 8.400 -1,575 o 4,320 21.120 10,500 160 9 9 Prev 1 of 3 !! Next > Answer is complete but not entirely correct. Fall $ 84,000 0 Winter $ 84,000 25,200 Spring $ 84,000 0 Summer $ 105,600 0 0 0 Regular time Overtime Inventory Backorder Hiring Layoff Total 800 15,750 8,000 0 0 0 0 DOO 300 0 810 0 $ 99.750 0 $ 109,200 0 $ 92,000 Annual cost 0 X $ 107,210 $ 408,160