In the calculations below after total revenue, why is Incremental Costs of 130,000 deducted but not the MOH of 9 per unit 5000 units deducted as well?

Also fixed selling expense why isn't that deductible?

PROBLEM 11-22 Special Order Decisions LO11-4 Polaski Company manufactures and sells a single product called a Ret. Operating at capacity, the company can produce and sell 30,000 Rets per year. Costs associated with this level of production and sales are given below: Unit Total $15 8 3 Direct materials .................. Direct labor...................... Variable manufacturing overhead .. Fixed manufacturing overhead... Variable selling expense ...... Fixed selling expense........ Total cost.... $ 450,000 240,000 90.000 270,000 120,000 180,000 $1,350,000 $45 2. Refer to the original data. Assume again that Polaski Company expects to sell only 25,000 Rets through regular channels next year. The U.S. Army would like to make a one-time-only purchase of 5,000 Rets. The Army would pay a fixed fee of $1.80 per Ret, and it would reimburse Polaski Company for all costs of production (variable and fixed) associated with the units. Because the army would pick up the Rets with its own trucks, there would be no variable selling expenses associated with this order. What is the financial advantage (disadvantage) of accepting the U.S. Army's special order? 2. Sales from the order: Reimbursement for costs of production (variable production costs of $26 plus fixed manufacturing overhead cost of $9 = $35 per unit; $35 per unit 5,000 units)................... Fixed fee ($1.80 per unit 5,000 units)..................... Total revenue Less incremental costs--variable production costs ($26 per unit * 5,000 units).......... Net increase in profils........... $175,000 9,000 184,000 130,000 $ 54,000