Where any period of an earner’s incapacity for work does not commence on the date of the accident, and the Corporation is of the opinion that relevant earnings ascertained in accordance with the foregoing provisions of this section do not fairly and reasonably represent the earner’s normal average weekly earnings at the commencement of the period of incapacity for work, the Corporation may, notwithstanding the foregoing provisions of this section, in its discretion determine an amount which in its opinion would fairly and reasonably represent his normal average weekly earnings at the time of the commencement of the period of incapacity for work, having regard to such information as it may obtain regarding his earnings before the time of the commencement of the period of incapacity for work and his earnings at the time of the commencement of that period, and to his work history and the period of his residence in New Zealand before the time of the period of incapacity for work; and any amount so determined shall be treated as if it was his relevant earnings for the purpose of assessing earnings related compensation during the particular period of incapacity for work:

“Provided that any determination made under this subsection shall not bind or prejudice the Corporation or limit or restrict its discretions or powers with regard to any assessment or determination of that person’s relevant earnings or loss of earning capacity during any other period of his incapacity for work to which the determination does not relate.

In determining the amount under subsection (10a) of this section, the Corporation may exercise the discretions and powers conferred on it by subsections (2), (3), and (4) of this section and by section 104a(3) of this Act as if references to the time of the accident and to the date of the accident in those subsections were references respectively to the time of the commencement of a period of incapacity for work and to the date of commencement of a period of incapacity for work.”