Answer:
The company pays $ 500 yearly fee to use Mega Tax Software which is record as fixed costs. Fixed costs do not differ with the variation in the manufacturing levels. Conversely, the fixed cost per unit declines as manufacturing increases, as the same fixed costs are extent over more units. Also the fixed costs per unit rises as the production decreases. Therefore when the production level increased from 300 units to 500 units, the fixed costs per unit reduced and since the variable cost per unit is the same at $ 10 per unit regardless of the levels of production, the total cost per return declines from $ 11.67 to $ 11.