Will Jones, LLP is a small CPA firm that focuses primarily on preparing tax returns for small businesses. The company pays a $500 annual fee plus $10 per tax return for a license to use Mega Tax software.

Required

What is the companys total annual cost for the Mega Tax software if:
Annual Fee $500
License Fee per Return $10		Total Cost
300	500 + 10 x 300 =	$3,500
400	500 + 10 x 400 =	$4,500
500	500 + 10 x 500 =	$5,500
What is the companys cost per return for the Mega Tax software if:
300	Total cost/units = $3,500 / 300 =	$11.67
400	$4,500 / 400 =	$11.25
500	$5,500 / 500 =	$11.00

Why does the cost per return differ at each of the three volume levels?