Answer:
The managerial accountant found out that the cost of the units previously sold was higher than the selling price per unit.
If the variance is unfavorable, it means that the total budgeted costs were larger than the total budgeted revenue. In this case the variance was $5,600 unfavorable. We are not told how many units were sold but it is obviously a mistake to sell products at a lower price than COGS. So the previous flexible budget was not properly prepared.
