(1) For the purposes of this Act, the taxable turnover of a dealer shall be that part of his gross turnover which remains after deducting therefrom--
(a) the aggregate value of the transactions specified in section 6;
(b) sale price on account of sales exempted under section 7;
(c) in the case of works contract, the amount remaining after deducting from the gross value of the contract the amount on account of the following, namely:--
(i) labour charges for execution of the works contract,
(ii) amount paid to sub-contractor on account of labour and services,
(iii) charges for planning, designing and architects fees,
(iv) charges for obtaining on hire, the machineries and tools used in the execution of the works contract,
(v) cost of consumables such as water, electricity, fuels, etc., used in execution of the works contract, the property in which is not transferred in the course of execution of a works contract,
(vi) cost of establishment of the contractor to the extent, it is relatable to supply of labour and services,
(vii) other similar expenses relatable to supply of labour and services,
(viii) profit earned by the contractor to the extent it is relatable to the supply of labour and services, and
(ix) goods or transaction exempted under section 6 or section 7;
(d) value of goods transferred otherwise than by way of sale;
(e) the value of goods sold but returned to the dealer within a period of six months from the date of the original sales and in respect of which the selling dealer has issued to the purchasing dealer a credit note specified in section 53;
(f) sale price at the subsequent stages of sale of such goods as are specified in Schedule IV as being subject to tax at the first point of their sale in the State of Bihar, if necessary evidence as required by sub-section (2) of section 13 are filed along with the return filed by the dealer under sub-section (3) of section 24.
(2) Where a dealer claims that he is not liable to pay tax on any part of his gross turnover in respect of any goods by reason of transfer of such goods by him to any other dealer or to his agent or to his principal, as the case may be, for sale, the burden of proving such claim shall be on the dealer and for this purpose, along with other evidences as may be prescribed, he shall furnish before the prescribed authority a declaration in a form and in the manner prescribed.