Final answer:
The introduction of sales commissions at Wislocki Corporation would increase net operating income by $166,650 per month, calculated by the increase in contribution margin and the decrease in fixed expenses due to lowered salaries.
Step-by-step explanation:
To determine the overall effect on the company's monthly net operating income of introducing sales commissions at Wislocki Corporation, one needs to calculate the change in contribution margin and the change in fixed expenses. The introduction of the sales commission would increase variable expenses by $11 per unit, but fixed expenses would decrease by $105,000 due to the reduction in salaries.
The additional 450 units sold at a contribution margin of $148 per unit would add $66,600 to the contribution margin ($148 per unit * 450 units). However, the additional variable costs due to the $11 commission per unit would be $4,950 ($11 per unit * 450 units). The net increase in contribution margin is therefore $61,650 ($66,600 - $4,950).
With the decrease in fixed expenses of $105,000, the total increase in net operating income would be $166,650 ($61,650 + $105,000). Therefore, the introduction of the sales commission would increase Wislocki Corporation's net operating income by $166,650 per month.