Fixed Overhead Variances Assume that ExxonMobil uses a standard cost system for each of its refineries. For the Houston refinery the monthly fixed overhead budget is $8,300,000 for a planned outputs of 5,000,000 barrels. For September, the actual fixed cost was $8,650,000 for 5,100,000 barrels. a. Determine the fixed overhead budget variance. b. If fixed overhead is applied on a per-barrel basis, determine the volume variance