(1) On receipt of a notice of payment under section 25(1), the Authority shall assess the amount of levy due in respect of the construction operations or the stage of the construction operations (if the construction operations are undertaken or carried out in stages) to which the payment relates.
(2) Where more than one payment is made or to be made in respect of construction operations or a stage of the construction operations, the assessment under subsection (1) shall be a provisional assessment and a final assessment shall be made on the final payment in respect of the construction operations, each stage of the operations or all stages of the operations, as is appropriate.
(3) On receipt of a notice of completion of construction operations or any stage thereof under section 25(2), the Authority shall, if no assessment under subsection (1) or (2) has been made, assess the amount of levy due in respect of the construction operations or the stage of the construction operations.
(4) Where construction operations are undertaken or carried out in stages the Authority may make a provisional assessment under subsection (3) on the completion of each stage of the construction operations and make a final assessment on the completion of all stages of the construction operations.
(4A) Notwithstanding subsections (1), (2) and (3), where construction operations are carried out under a term contract, the Authority may defer the making of any assessment under subsection (1), (2) or (3) until such time as the Authority considers appropriate. (Added 3 of 2004 s. 12)
(5) The Authority may assess the amount of levy due in respect of the construction operations or stage thereof which have or has been completed notwithstanding that no notice has been given to the Authority under section 25.
(6) Where it appears to the Authority that an assessment of levy has been made at less than the proper amount, then, subject to subsection (9), the Authority may at any time make an additional assessment of levy due in respect of construction operations or a stage of construction operations.
(7) If a contractor fails to give any notice required to be given by him under section 25 and does not give a reasonable excuse therefor within such period as the Authority may allow in any case, the Authority may, in addition to the levy assessed under this section and payable by the contractor, impose a surcharge on the contractor not exceeding twice the amount of the levy so assessed.
(8) Any assessment of levy or imposition of surcharge under this section shall be notified in writing by the Authority. (Replaced 3 of 2004 s. 12)
(8A) A levy or surcharge shall not be payable by a contractor-

(a) if he has not been notified by the Authority of an assessment of such levy or imposition of such surcharge, as the case may be, under subsection (8); or
(b) to the extent that the levy or surcharge, as the case may be, has been paid by any other contractor unless the levy or surcharge, as the case may be, may be required or ordered to be refunded or repaid to that other contractor under section 27(1C), 29(4) or 30(4). (Added 3 of 2004 s. 12)

(a) 2 years after the completion of the operations; or (Amended 3 of 2004 s. 12)
(b) 1 year after evidence of facts, sufficient in the opinion of the Authority to justify the making of the assessment or the imposition of the surcharge comes to its knowledge,

(a) 2 years after the completion of all construction operations to which the contract relates;
(b) 2 years after the expiration of the period within which all construction operations to which the contract relates have to be completed as provided for by the contract; or
(c) 1 year after evidence of facts, sufficient in the opinion of the Authority to justify the making of the assessment or the imposition of the surcharge comes to its knowledge,