Cases where rent to be deemed and not to be deemed to be increased

(1) Where, as the result of any alteration of the terms of the tenancy, the terms on which any premises are held are on the whole less favourable to the tenant than the previous terms, the rent shall be deemed to be increased for the purposes of this Part whether the sum payable as rent is increased or not. (2) Where, as the result of any alteration of the terms of the tenancy, the terms on which any premises are held are not on the whole less favourable to the tenant than the previous terms, the rent shall not be deemed to be increased for the purposes of this Part whether the sum payable as rent is increased or not.