A "Provided that, in the case of sale of goods during their movement from one State to another, being a sale subsequent to the first sale in respect of the same goods and being also a sale which does not fall within sub section (2) of section 6, the tax shall be levied and collected (a) where such subsequent sale has been effected by a registered dealer, in the State from which the registered dealer obtained or, as the case may be could have obtained, the form prescribed for the purposes of clause (a) of subsection (4) of section 8 in connection with the purchase of such goods, and (b) where such subsequent sale has been effected by an unregistered dealer in the State from which such subsequent sale has been effected." (b) in sub section (2), before the words "compounding of offences", the words "charging or payment of interest", shall be inserted and shall be deemed always to have been inserted .