Manta Ray Company manufactures diving masks with a variable cost of $25. The masks sell for $34. Budgeted fixed manufacturing overhead for the most recent year was $792,000. Actual production was equal to planned production.
Required: Under each of the following conditions, state (a) whether operating income is higher under variable or absorption costing and (b) the amount of the difference in reported operating income under the two methods. Treat each condition as an independent case.
1. Production ............................................... 110,000 units
Sales ........................................................ 108,000 units
2. Production ............................................... 90,000 units
Sales ........................................................ 95,000 units
3. Production ............................................... 79,200 units
Sales ........................................................ 79,200 units

that's because variable will consider the entire amount of fixed cost as cost of the period while, absorption will capitalizethe fixed cost through inventory. If production matches sales then in both cases the fixed cost are entire expressed in the income statement. If they don't the difference is the difference times unit fixed cost.

(First Case)

fixed cost per unit $792,000 / 110,000 = $7.2

difference (110,000 - 108,000) x $7.2 = $14,200

(Second Case)

fixed cost per unit: 792,000 / 110,000 = $8.8

difference (90,000 - 95,000) x $8.8 = $44,000

(Third Case)

They match thus, no difference arises.