28 January 2014
Mr Sudalaimani, Here many points raised by you are of just mutual agreement only.The point of taxation is the moment of receiving consideration(payment) for the work done by a contractor.Point of invoicing is as per agreed terms e.g. 25% on completing foundation,next 25% on construction of walls etc.Or some percentage of the total amount can be received as advance to be adjusted against the final invoice.In government works invoicing is done at each stage, called as RA bills,and final bill will be on completion as per agreement.Value estimation at each stage is done as per agreement.Invoicing whether at each stage depends upon the agreement.Method of valuation is an engineering subject and there are various formulae.....mjk