George Jack operates a small machine shop. He manufactures one standard product available from other similar businesses, and he also manufactures products to customer order. His accountant prepared the annual income statement shown below:

The depreciation charges are for machines. The power charge is apportioned based on estimated power consumed The rent is for the building space that has been leased for $10$ years at $$14,000$ per year. The rent and heat and light are apportioned to the product lines based on amount of floor space occupied. All other costs are current expenses identified with the product Ime causing them

A valued custom parts customer has asked Mr$.$ Jack if he would manufacture $5,000$ special units for him. Mr$.$ Jack is working at capacity and would have to give up some other business in order to take this business. He can't renege on customer orders already agreed to$,$ but he could reduce the output of his standard product by about one$-$ half for one year while producing the specially requested custom part. The customer is willing to pay $$16\mathrm{.}00$ for each part. The material cost will be about $54\mathrm{.}50$ per unit and the labor will be $$8\mathrm{.}00$ per unit. Mr$.$ Jack will have to spend $$4,500$ for a special device that will be discarded when the job is done. Should Mr$.$ Jack take the order?

Calculate the following costs related to the $5,000-$unit custom order.

$(1)$ The differential cost of the order.

$(2)$ The full cost of the order.

$(3)$ The opportunity cost of taking the order.

$(4)$ Sunk Cost