Why is a variable costing format more useful for performance evaluation purposes than an absorption costing format?

Profit Variance Analysis, Containers, Inc. (August) Sales Actual (based on 50,000 units) Manufacturing Variances Marketing and Administrative Variances Sales Flexible Budget Activity Price (based on (Volume) Variances 50,000 units) Variance Master Budget (based on 45,000 units) Sales revenue $500,000 $7,500 U $507,500 $50,750 F $456,750 Less: Variable manufacturing costs 244,000 $44,000 U - 200,000 20,000 U 180,000 Variable marketing and administrative costs 52,000 - Contribution margins 204,000 44,000 U $2,000 U 2,000 U 50,000 5,000 U 45,000 7,500 U 257,500 25,750 F 231,750 Less: Fixed manufacturing costs 83,000 3,000 U 80,000 80,000 Fixed marketing and administrative costs 96,000 Operating profits $ 25,000 $47,000 U 4,000 F $2,000 F $7,500 U 100,000 $ 77,500 100,000 $25,750 F $ 51,750 *$2,000 = $.04 x 50,000 = ($1.04 $1.00) 50,000 units. Total variance from flexible budget $52,500 U Total variance from master budget = $26,750 U