應該是如下所列算式:
$0.99– $50.00 11.0% of the total amount of the sale.
$50.01–$1000.00 11.0% of the initial $50.00, plus 6.0% of the remaining balance ($50.01–$1,000.00) of the total amount of the sale
$1000.01 or more 11.0% of the initial $50.00, plus 6.0% of the next $50.01–$1,000.00, plus 2.0% of the remaining balance
($1,000.01–total cost to buyer) of the total amount of the sale.