Required: (1) Calculate the sales variances that assess the performance of the two individual sales managers. (2) Calculate the sales variances that assess the sales performance of the operation manager. (3) Comment on why you have produced different variances in (1) and (2) and on possible causes of the variances. HS Buildings Ltd fabricates, assembles and sells a range of wooden buildings for use as garden sheds, home offices, sun lounges, etc. After several years of successful sales at home, the company has now developed sufficient export business to merit two sales managers, UK and export, who report to the operations manager. Overall sales performance is the responsibility of the operations manager, individual UK or export sales are the responsibility of the two sales managers. The budget for 19X8 showed the following: UK Export Total Buildings sold 300 100 400 Average selling price $7,500 $8,000 Average cost $5,000 $6,000 Actual results were as follows: Buildings sold 320 90 410 Average selling price $7,400 18,200 Average cost $5,100 f6,100 An analysis of sales performance is needed for presentation to the board of HS Buildings Ltd