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 $9,900,000 for a planned output of 6,000,000 barrels. For September, the actual fixed cost was $10,115,000 for 5,950,000 barrels. a. Determine the fixed overhead budget variance. b. If fixed overhead is applied on a per-barrel basis, determine the volume variance