The supplier has charged freight on sale invoice. This means that the supplier would have paid freight to the transporter and is now recovering the same from the purchaser. In this case supplier is supposed to pay service tax as he has paid freight amount.
If the supplier is just arranging for the transport then he is not supposed to charge freight on invoice. Instead he should write as to pay basis and then the transporter will issue consignment note in the name of purchaser and purchaser will make the freight payment. And freight will be paid by purchaser.
Based on the above para querist should check the actual background as to who is going to pay freight. Thanks.