It's because S&H is taxable in NJ.
Are shipping and handling subject to sales tax?
Effective October 1, 2005, the law provides for a new definition of "delivery charges." For transactions occurring on or after October 1, 2005, handling charges are included within the definition of delivery charges, and are therefore exempt from tax whether or not they are separately stated to the purchaser.
Prior to October 1, 2005, a separately stated charge for the transportation (shipping) of tangible personal property from the vendor to the customer was not subject to New Jersey sales tax. Depending on the circumstances, a separately stated “handling” charge could be considered part of the taxable receipt (amount on which sales tax is due) because it occurs prior to actual shipment. However, when “shipping and handling” charges were billed together, both amounts were considered exempt transportation charges for New Jersey sales tax purposes.
As of October 1, 2006, the exemption for delivery charges imposed by the seller is repealed for taxable goods and services. For deliveries on and after October 1, 2006, if a shipment includes both taxable and exempt property, the seller should allocate the delivery charge based on either the total sales price or the total weight, and collect tax on the portion of the delivery charge allocated to the taxable goods. In such mixed transactions, if the seller does not allocate the delivery charge, the entire delivery charge is taxable.