The level of inventory of a manufactured product has increased by $8,579$ units during a period. The following data are also available:

Variable Fixed

Unit manufacturing costs of the period $$13\mathrm{.}00$ $$4\mathrm{.}50$

Unit operating expenses of the period $1\mathrm{.}502\mathrm{.}50$

The effect on operating income if variable costing is used rather than absorption costing would be a$($n$)$: