Gerhan Company's flexible budget for the units manufactured in May shows $15,640 of total factory overhead; this output level represents 70% of available capacity. During May, the company applied overhead to production at the rate of $3.00 per direct labor hour (DLH), based on a denominator volume level of 6,120 DLHs, which represents 90% of available capacity. The company used 5,000 DLHs and incurred $16,500 of total factory overhead cost during May, including $6,800 for fixed factory overhead. What is the factory overhead efficiency variance (to the nearest whole dollar) for Gerhan Company in May, under the assumption that the company uses a two-variance breakdown (decomposition) of the total overhead variance