95淡大會研成管會-差異分析 - 會計

Morano Company budgeted production and sales at its maximum capacity
of 20,000 units for 20X6.However, Morano was able to produce and sell
only 18,000 units for the year.There are no beginning pr ending inventories.
Other data for 20X6 follow:

Budgeted fixed overhead costs $500,000
Budgeted selling price $100
Budgeted variable cost per unit $40

Compute sale-volume variance,production-volume variance,and
operating income volume variance.What do each of these variance measure

書上解答如下
固定製造費用=$500,000/20,000=$25
sale-volume variance=($100-$40)*(18,000-20,000)=-$120,000(不利)
production-volume variance=$25*(20,000-18,000)=$50,000(不利)
Operating income volume variance=$120,000+$50,000=$170,000(不利)

我的想法是
sale-volume variance=$100*(18,000-20,000)=-$200,000(不利)
production-volume variance=$65*(18,000-20,000)=-$130,000(有利)
Operating income volume variance=$200,000-$130,000=$70,000(不利)

請問我的想法錯在哪裡,謝謝了

--