keystone dec 2011

During the year Keystone manufactured an item of plant for its own use. The direct materials and labour were $3 million and $4 million respectively. Production overheads are 75% of direct labour cost and Keystone determines the final selling price for goods by adding a mark-up on total cost of 40%. These manufacturing costs are included in the relevant expense items in the trial balance. The plant was completed and put into immediate use on 1 April 2011 The plant in the trial balance will be depreciated by $6 million ((44,500 – 14,500) x 20%) for the year and have a carrying amount at 30 September 2011 of $24 million please why 10 000 of the production of plant are reduce from the cost of plant in the sofp? 44 500- 14500 -10 000. but the answer ignored those $10 000 thx