Please consider the following propositions:
Notification No 8/2018-Central Tax (rate) reads as under:
G.S.R. 82 (E).- In exercise of the powers conferred by sub-section (1) of section 11 of the Central Goods and Services Tax Act, 2017 (12 of 2017), the Central Government, on being satisfied that it is necessary in the public interest so to do, on the recommendations of the Council, hereby exempts the central tax on intra-state supplies of goods, the description of which is specified in column (3) of the Table below, falling under the tariff item, sub-heading, heading or Chapter as specified in the First Schedule to the Customs Tariff Act, 1975 (51 of 1975), as are given in corresponding entry in column (2), from so much tax as specified in Schedule IV of Notification No. 1/2017 -Central Tax (Rate), as is in excess of the amount calculated at the rate specified in the corresponding entry in column (4), of the said Table, on the value that represent margin of the supplier, on supply of such goods.
The above Notification "exempts" intra-state supplies of goods falling under the Table thereto, from the tax specified in Notification No.1/2017 as in excess of amount calculated at rate specified therein on the margin. (Therefore, one needs to calculate the tax as per Notification No.1/2017 and tax under this Notification and the difference thereof is exempted). In other words, the exmeption appears to be granted, not on the supply itself but only on the marginal tax.
Therefore, in this case, the rate of tax of 1% (0.5% + 0.5%) requires to be computed on the entire turnover, and not on the margin.