1月份 變動成本法下之營業利益 | $160,000 | 加:期末存貨所含之FOH (300*$400) | 120,000 | 歸納成本法下之營業利益 | $280,000 |

由上述可知,因公司本年度生產量大於銷售量,存貨變動增加300單位,致使採用歸納成本法 下之固定製造費用僅有700*$400=$280,000列入至I/S之COGS,變動成本法係將固定製造費 用在當期全數列入費用,所以產生歸納之O.I大於變動之O.I.

2月份 變動成本法下之營業利益 | $260,000 | 減:期初存貨所含之FOH (300*$400) | (120,000) | 加:期末存貨所含之FOH (300*$400) | 120,000 | 歸納成本法下之營業利益 | $260,000 |

由上述可知,因公司本年度生產量等於銷售量,存貨變動未產生變動,致使採用歸納成本法下 之固定製造費用有800*$400+$80,000=$400,000列入至I/S之COGS,變動成本法係將固定製 造費用在當期全數列入費用,所以產生歸納之O.I等於變動之O.I.

3月份 變動成本法下之營業利益 | $960,000 | 減:期初存貨所含之FOH (300*$400) | (120,000) | 加:期末存貨所含之FOH (50*$400) | 20,000 | 歸納成本法下之營業利益 | $860,000 |

由上述可知,因公司本年度生產量小於銷售量,存貨變動減少250單位,致使採用歸納成本法 下之固定製造費用有1,500*$400-$100,000=$500,000列入至I/S之COGS,變動成本法係將固 定製造費用在當期全數列入費用,所以產生歸納之O.I小於變動之O.I.

(1) Zwatch CompanyIncome StatementFor the year ended December 31, 2014 | Revenues (345,400 $22 per unit) | | $7,598,800 | Variable costs | | | Variable cost of goods sold (345,400*$5.1) | $1,761,540 | | Variable marketing costs (345,400units$1.1 per unit) | 779,940 | 2,541,480 | Contribution margin | | 5,057,320 | Fixed costs | | | Fixed manufacturing costs | 1,440,000 | | Fixed operating costs | 1,080,000 | 2,520,000 | Operating income | | $2,537,320 |
@FOH=$1,440,000/300,000=$4.8 Zwatch Company Income StatementFor the year ended December 31, 2014 | Revenues (345,400 $22 per unit) | | $7,598,800 | Cost of goods sold | | | Cost of goods sold (345,400 * $9.9) | $3,419,460 | | Add unfavorable production volume variance (5,100*$4.8) | 24,480a U | 3,443,940 | Gross margin | | 4,154,860 | Operating costs | | | ariable marketing costs (345,400units$1.1 per unit) | 779,940 | | Fixed operating costs | 1,080,000 | 1,859,940 | Operating income | | $2,294,920 | | 2. 變動成本法下之營業利益 | $2,537,320 |