Section 63. Aggregate amount of allowance granted to, and deduction from rent allowed to, excluded proprietor

The aggregate amount of any allowance under section sixty-one, and of the difference between the rent fixed under section sixty-two and the rent which the excluded proprietor would be liable to pay if he were a tenant-at-will, shal1 not be less than five or more than fifteen per cent. on the amount of the assessment offered to him by the Settlement-officer.