Dubberly Corporation's cost formula for its manufacturing overhead is $31,300 per month plus $52 per machine-hour. For the month of March, the company planned for activity of 8,040 machine-hours, but the actual level of activity was 7,950 machine-hours. The actual manufacturing overhead for the month was $472,630. The spending variance for manufacturing overhead in March would be closest to: $23,250 U $23,250 F $27.930 F $27,930 U