Oxford Engineering manufactures small engines. The engines are sold to manufacturers who install them in such products as lawn mowers. The company currently manufactures all the parts used in these engines but is considering a proposal from an external supplier who wishes to supply the starter assemblies used in these engines. The starter assemblies are currently manufactured in Division 3 of Oxford Engineering. The costs relating to the starter assemblies for the past 12 months were as follows: Direct materials $200,000 Direct manufacturing labor 150,000 Manufacturing overhead 400,000 Total $750,000 Over the past year, Division 3 manufactured 150,000 starter assemblies. The average cost for each starter assembly is $5 ($750,000