(b)no person shall be required under this section to expend a sum, exceeding five times the holding tax any such building with the land assessed with it as part of the some premises or in the case of buildings exempted under Section 132 five times the holding tax which would be payable on such buildings with the land which be assessed with it to the holding tax, if such buildings were not exempt and if any amount exceeding the said sum is expended, the excess shall be born by the Municipality.