The following is total monthly budgeted cost and activity information for the four activity centers in the billing department of Oregon Power Company: Cost Driver Activity Center Statement inquiry Correspondence Account billing Payment verification Variable $77,792 $9,548 $125,000 $10,140 Fixed $ 158,000 $22,000 $83,000 $80,000 3,200 labor hours 2,800 letters 2,500,000 lines 19,500 accounts In September, actual total costs and activity were as follows: Total Costs $234,844 Driver Amount 3,120 labor hours Activity Center Statement inquiry Correspondence Account billing Payment verification $31,587 2,840 letters 2,380,000 lines $201,549 $89,056 19,320 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): Correspondence Account billing