GST on retained SKO applies only to the quantity used for LAB; returned SKO taxable only if supplied to others. GST on superior kerosene oil (SKO) supplied for extraction of n Paraffin for Linear Alkyl Benzene (LAB) is payable by the refinery only on the net quantity of SKO retained by the LAB manufacturer for manufacture; SKO returned to the refinery in that transaction is not taxed unless the refinery later supplies it to another person.