Sarah Pty Ltd is a manufacturing firm that produces customized office stationeries according to customers' orders. The company adopts the job order costing system, and manufacturing overhead is allocated to production at a predetermined overhead rate of 70 percent of direct labour cost. According to the company's policy, any over- or under-allocated manufacturing overhead is written off to the cost of goods sold. The firm does not have any work-in-process at the beginning or end of the quarter. Below is the financial information for the 4th quarter of 2022: Direct material used $180,000 Direct labour cost incurred $650,000 Indirect labour cost incurred $120,000 Indirect material used $80,000 Selling and administrative expenses $550,000 Depreciation of factory building and equipment $160,000 Insurance on factory and equipment $50,000 Electricity for factory $25,000 Required: (a) Estimate the cost of goods manufactured for the company for the 4th quarter of 2022. Clearly show the workings of the calculation. (3 marks) (b) Calculate the difference between the actual manufacturing overhead cost incurred and manufacturing overhead cost allocated. Identify whether it is under- allocated or over-allocated. Clearly show the workings of the calculation