Morgan Tax Company considers 6,000 direct labor hours or 300 tax returns its normal monthly capacity. Its standard variable overhead rate is \($5\) per direct labor hour. During the current month, \($25,400\) of variable overhead cost was incurred in working 5,600 direct labor hours to prepare 270 tax returns. Determine the following variances, and indicate whether each is favorable or unfavorable:

a. Variable overhead spending

b. Variable overhead efficiency