Act is silent whether it is collected from the customer or not and NBT is payable for the full amount before VAT. For instance if a company charges only 2% on Rs.100 bill, then the company has to pay the inland revenue 2% of 102 which is 2.04. That is why companies are charging 2/98 from the bill value. If you do not want NBT to be borne by you, then you should find another supplier who does not charge NBT from customers.