For the purpose of calculating a superannuation allowance, whether granted before or after the passing of this Act, under section five of the Belfast Corporation Act (Northern Ireland), 1943 M1, as amended by section seven of the Belfast Corporation (General Powers) Act (Northern Ireland), 1948 M2, the [F2 council of the City of Belfast] may at their discretion disregard wholly or partly any amount by which any such sum as is referred to in sub-paragraph (ii) of paragraph ( b) of sub-section (1) of the said section seven exceeds the sum of [F3 £1.30].]