Notwithstanding anything contained in this Act or rules made thereunder or in any judgment, decree or order of any court, tribunal or appellate authority, works contractors who have opted for and paid compounded tax under clause (a) of section 8 of the Act for the years up to 2014-15 in respect of works relating to installation of kitchen cabinet, aluminium fabrication and air conditioning plants in which the transfer of materials is in the form of goods and if all the purchases for executing such contracts are from within the State, may pay an additional tax of two per cent on the whole contract amount, and on payment of such tax, no further proceedings under this Act, including any assessment or penalties shall lie against such contractors