The Harris and Martin Dental Clinic provides both preventive and orthodontic dental services. The two owners, Mark Harris and Betty Martin, operate the clinic as two separate investment centres: preventive services and orthodontic services. Each owner is in charge of one centre: Mark for preventive services and Betty for orthodontic services. Each month, they prepare an income statement on the two centres to evaluate performance and make decisions about how to improve the clinic's operational efficiency and profitability.

Recently, they have been concerned about the profitability of the preventive services operations. For several months, the centre has been reporting a loss. In addition, the owners know that the investment in operating assets at the beginning of the month was $$102,300,$ and it was $$97,700$ at the end of the month. They have asked for you to evaluate their current performance reporting system. Shown below is the responsibility report for the month of May $2022$:

$\backslash$table$[[,$Actual,,$\backslash$table$[[$Difference$],[$from Budget$]]],[$Service revenue,$$45,300,$$$2,100,$Favourable$],[$Variable costs$],[$Filling materials,$7,100,400,$Unfavourable$],[$Novocaine$,4,300,200,$Unfavourable$],[$Supplies$,2,000,300,$Favourable$],[$Dental assistant wages,$2,600,-0-,$Neither Favourable nor Unfavourable$],[$Utilities$,450,50,$Unfavourable$],[$Total variable costs,$16,450,350,$Unfavourable$],[$Fixed costs$],[$Allocated portion of receptionist's salary,$2,900,300,$Unfavourable$]]$