TipTop Flight School offers flying lessons at a small municipal airport. The school's owner and manager has been attempting to evaluate performance and control costs using a variance report that compares the planning budget to actual results. A recent variance report appears below: TipTop Flight School Variance Report For the Month Ended July 31 Actual Planning Results Budget Variances Lessons 175 170 Revenue 38,390 37,400 990 F Expenses 10,880 10,710 Instructor wages 170 U Alrcraft depreciation 7,000 200 U 6,800 Fuel 3.680 3.230 450 U 2,530 130 U Maintenance 2,660 Ground facility expenses 2.425 2.490 65 F Administration 4,270 4.360 90 F Total expense 30,915 30,120 795 U 7.475 7.280 95 F Net operating income After several months of using such variance reports, the owner has become frustrated. For example, she is quite confident that instructor wages were very tightly controlled in July but the report shows an unfavorable variance. The planning budget was developed using the following formulas, where q is the number of lessons sold: Cost Formulas $2209 Revenue $630 Instructor wages Aircraft depreciation $40 Fuel $19q Maintenance S 660 S11 Ground facility expenses $1,640 559 $4.190 Siq Administration