(1) Subject to sections 464 and 468, the Authority must, within 90 days after receiving an application under section 462 for review of a reviewable amount, conduct the review and make a determination under section 468.
(2) The period specified in subsection (1) may be extended—
(a) by agreement between the Authority and the employer; or
(b) if the Authority authorises a person under section 553 to conduct an inspection, by any further period as is specified by the Authority in a notice in writing given to the employer before the end of that period.