In detail, why is the costing operating income different from the absorption costing operating income?

	Absorption Costing	Variable Costing
Sales	$530,000	$530,000
Cost of goods sold (COGS)	450,000	210,000
Gross margin	$ 80,000	$320,000
Overhead volume variance	(15,000)	0
Overhead budget variance	2,800	2,800
Adjusted gross margin	$ 67,800	$322,800
Less: Fixed manufacturing overhead	0	270,000
Less: Selling, general, and administrative	58,000	58,000
Operating income	$ 9,800	$(5,200)