Bracken Clinic uses client-visits as its measure of activity. During September, the clinic budgeted for 2,100 client-visits, but its actual level of activity was 2,140 client-visits. The clinic has provided the following data concerning the formulas used in its budgeting and its actual results for September: Fixed element per Variable element per month client-visitRevenue $44.50Personnel expenses $26,100 $12.60Medical supplies 600 7.20Occupancy expenses 6,500 2.40Administrative expenses 3,100 0.10Total expenses $36,300 $22.30Actual results for September:Revenue $93,240 Personnel expenses $50,754 Medical supplies $15,328 Occupancy expenses $11,646 Administrative expenses $3,394 The overall revenue and spending variance (i. e., the variance for net operating income in the revenue and spending variance column on the flexible budget performance report) for September would be closest to .