CK Manufacturing Company's new automated system is in its first year of operation. The company produces inventories for sale in Hong Kong and other nearby regions. The new Chief Financial Officer (CFO) has instructed you as the senior accountant to find the best way to estimate the overhead costs of operations for budgetary purposes. For the first six months of operations, the following data were collected: Kilowatt-hours 4,520,000 4,340,000 4,500,000 4,300,000 4,200,000 4,120,000 Machine hours 3,860 3,650 3,900 January February March April May June Total Overhead Costs $338,000 336,800 339,200 336,800 326,000 320,000 3,200 3,210 3,100 Required: The CFO intends to use the high-low method for cost estimation based on the operations of the first six months. Advise the company which cost driver is more accurate for estimating total overhead cost if the company finally ran the machines for 3,000 hours and used 4,000,000 kilowatt-hours of power with actual overhead costs totalled $318,000 in July. Discuss any other methods that can be bdopted to improve the accuracies of cost estimation. (Total: 10 marks)