(5)Notwithstanding anything contained in sub-sections (1) and (2) no person shall be liable-(a)to pay tax to the Municipality during any half-year on account of any animal or vessel in respect of which the full tax for the same half-year has already been paid to the Municipality by some other person; or(b)to pay to the Municipality on account of any animal or vessel in respect of which tax has already been paid to any other local authority whether under this Act, or any other Act in force, more than the excess, if any, of the tax payable in the Municipality in respect of such animal or vessel over the tax already paid to the other local authority.