Arches Manufacturing had always made its components in$-$house. However, Canyonlands Component Works had recently offered to supply one component, DA$,$ at a price of $$51$ each. Arches uses $12,500$ units of component DA each year. The cost per unit of this component is as follows:

Direct materials $$25\mathrm{.}00$

Direct labor $6\mathrm{.}25$

Variable overhead $15\mathrm{.}75$

Fixed overhead $7\mathrm{.}00$

Total $$54\mathrm{.}00$

Assume that $80\%$ of Arches Manufacturing's fixed overhead for component would be eliminated if that component were no longer produced.

If Arches decides to purchase the component from Canyonlands, by how much will operating income increase or decrease $($as compared to making the component in$-$house$)?$

By what dollar amount would the per$-$unit relevant fixed cost have to decrease before Arches would be indifferent $($i$.$e$.,$ incur the same cost$)$ between "making" versus "purchasing" the component?