(aa) in the case of an enhancement levy, the amount by which the estimated difference as determined by the arbitrator is less than the amount last proposed in writing as the estimated difference by the local authority before such dispute arose bears to the amount by which the estimated difference so determined is greater than the amount last proposed in writing as the estimated difference by the owner before such dispute arose, and

(bb) in the case of compensation, the amount by which the estimated difference as determined by the arbitrator is greater than the amount last proposed in writing as the estimated difference by the local authority before such dispute arose bears to the amount by which the estimated difference so determined is less than the amount last proposed in writing as the estimated difference by the owner before such dispute arose, and

(b) in the case of a dispute deemed in terms of subsection (5) (b) to have arisen, against the local authority and the owner, who shall be jointly and severally liable therefore.

(7) The payment of an enhancement levy or compensation shall be in addition to any other obligation imposed on the local authority or the owner of the land concerned in consequence of the provisions of the relevant scheme and such levy or compensation shall be payable—

(a) in the case of an enhancement levy—

(i) before such land or any portion thereof is put or converted to any use which is authorized or permitted by the provision contemplated by subsection (1) but which was not so authorized or permitted before the fixed date, or

(ii) before such land or any portion thereof, other than a portion which is subject to a direction issued in terms of subsection (9), is transferred to any person, and

(b) in the case of compensation, within a period of six months from the date of the agreement contemplated by subsection (4) or (5) (b) or of the award made by an arbitrator in terms of this section, as the case may be.

(8) Whenever it is proposed to transfer land in respect of which an enhancement levy is due but has not yet been paid or to transfer any portion of such land and—

(a) the obligation to transfer such land or such portion arises from or in consequence of a contract which was entered into by the owner and the proposed transferee before the fixed date, or

(b) the owner of such land and the proposed transferee have in writing agreed that such transferee accepts liability for payment of such levy,

the Administrator may, after consultation with the owner, the proposed transferee and the local authority, determine that such owner shall, on the transfer of such land or of such portion to such transferee, be wholly or partly exempt from liability for payment of such levy and upon such transfer such transferee shall, subject to any further such exemption, become liable for payment, on the occurrence of any event contemplated by subsection (7) (a), of such levy to the extent to which such levy has not been paid by such owner. (9) (a) Where a portion of the land referred to in subsection (1) (a) is required by the local authority for any purpose whatsoever which it is from time to time by law empowered or required