5.On a reading of the assessment order dated 02.07.2004, I find that the reply given by the dealer was examined and the Assessing Officer found that the dealer has used chemicals incidental to the contract work of pre-coating and they has collected labour charges for such work and therefore, concluded that the value of chemicals used in the execution of contract work is liable to tax @ 12%, since the chemical were procured from outside State. With regard to the remaining turnover which pertains to labour charges, it was held that it was not taxable in the impugned notice. There is no averment as to how, the respondent has come to the conclusion that the power under Section 16 of the TNGST Act has been invoked and as to how, comes to the conclusion that taxable turnover has escaped assessment or has been assessed at a lower rate. Thus, in the absence of any such proposal, the impugned notice has to be regarded as one change of opinion and therefore, the respondent has no jurisdiction to revise the assessment order dated 02.07.2004.