To determine the taxable turnover of sales, the following amounts shall, subject to the conditions specified, be deducted from the gross turnover of sales-

(a) the turnover of sale of goods exempt from tax under section 17;

(b) the turnover of sale of goods, subject to production of evidence to the satisfaction of the Commissioner, taking place -;

(i) in the course of inter-State trade or commerce; or

(ii) outside the state; or

(iii) in the course of import into or export out of territory of India;

(c) the turnover of sale of goods to a dealer under-

(i) a SEZ, or

(ii) a STP, or

(iii) an EHTP,

subject to production of evidence to the satisfaction of the Commissioner;

(d) the turnover of sale of goods to a EOU, subject to production of evidence to the satisfaction of the Commissioner;

(e) in case of works contract, the expenditure incurred towards labour and service, subject to the condition that evidence in support of such expenses are produced to the satisfaction of the Commissioner :

Provided that where a dealer executing works contract, fails to produce evidence in support of expenses towards labour and service as referred to above or such expenses are not ascertainable from the terms and conditions of the contract or the books of accounts maintained for the purpose, expenses on account of labour and service shall be determined at the rate specified in the Appendix.