The following is total monthly budgeted cost and activity information for the four activity centers in the billing department of Oregon Power Company: Variable Fixed $77,220 $151,000 Activity Center Statement inquiry Correspondence Account billing Payment verification $9,576 Cost Driver 3,300 labor hours 2,800 letters 2,500,000 lines 20,500 accounts $20,000 $86,000 $79,000 $150,000 $9,020 In September, actual total costs and activity were as follows: Activity Center Statement inquiry Correspondence Account billing Payment verification Total Costs $233,375 $29,866 $233,944 $88,721 Driver Amount 3,500 labor hours 2,870 letters 2,480,000 lines 20,380 accounts Required Compute the flexible-budget variances for the following two activity cost items (round unit costs to two decimal places and enter favorable variances as positive numbers and unfavorable variances as negative numbers): Account billing Correspondence