Q13. Grainger Ltd makes sofa covers which are sold directly to the public via the company's website. The business has expanded over the last couple of years and has recently appointed you as management accountant to replace Mark Arthurs, the retiring ofce manager. To help you on your arrival, Mark Arthurs has supplied the following standard costing data. based on observations and nancial records. Quantity of resource Cost per unit of Standard cost resource (2) per unit (it) Direct materials 14 m2 (square metres) 20 280 Direct Labour 10 hours 11.50 E Total Planned output for October (your rst month in the post) had been 2.300 units. however, due to the current trend for refurbishing existing fumiture rather than replacing it. the actual output in the month was 2,622 units. The month had. however, been challenging. with staff shortages being plugged using agency staff and fabric is difcult to source due to supply chain issues. The report of actual costs incumed in October is as follows: Quantity of resource Total Cost () Direct materials 38.019 m2 (square metres) 798.399 Direct Labour 31.464 hours 3?3.635 Total 1 172 034 In a meeting to discuss cost control in the period. Stuart Brown. the production manager. made the following statement: \"in preparing for this meeting I've done some calculations: output was 14% higher than planned but our cost per unit was only 13.2% higher than standard: what a fantastic job the team's done in controlling our costs!" Required: a) Calculate the total direct materials variance and total direct labour variance. together with their respective sub-variances. (21 marks) b) Show how Stuart derived the percentages quoted in his statement and consider its validity. Discuss whether or not you agree that costs have been well controlled in the period . (4 marks)