$\mathrm{}$Stephans Corporation currently manufactures a subassembly for its main product. The costs per unit are as follows: 

 

Direct materials $ $1\mathrm{.}00$

Direct labor $10\mathrm{.}00$

Variable overhead $5\mathrm{.}00$

Fixed overhead $8\mathrm{.}00$

Total $$24\mathrm{.}00$

Bill Company has contacted Stephans with an offer to sell them $5,000$ of the subassemblies for $$22\mathrm{.}00$ each. Stephans will eliminate $$25,000$ of fixed overhead if it accepts the proposal.

Should Stephans make or buy the subassemblies? What is the difference between the two alternatives?