The following is total monthly budgeted cost and activity information for the four activity centers in the billing department of Oregon Power company: \begin{tabular}{|l|c|c|c|} \hline Activity Center & Variable & Fixed & Cost Driver \\ \hline Statement inquiry & $76,164 & $165,000 & 3,300 labor hours \\ \hline Correspondence & $9,940 & $26,000 & 2,800 letters \\ \hline Account billing & $156,000 & $72,000 & 2,600,000 lines \\ \hline Payment verification & $8,880 & $79,000 & 18,500 accounts \\ \hline \end{tabular} In September, actual total costs and activity were as follows: \begin{tabular}{|l|c|c|} \hline Activity Center & Total Costs & Driver Amount \\ \hline Statement inquiry & $245,800 & 3,470 labor hours \\ \hline Correspondence & $36,559 & 2,940 letters \\ \hline Account billing & $225,300 & 2,560,000 lines \\ \hline Payment verification & $87,734 & 18,400 accounts \\ \hline \end{tabular} Required negative numbers): Account billing incorrect Correspondence incorrect