(1) For the purposes of this Part, reckonable earnings may be calculated or estimated, either for a person or a class of persons, in the manner, by reference to the matters and on the basis that may be prescribed.
(2) Regulations may provide for the calculation of the amounts payable in respect of employment contributions in accordance with prescribed scales, and for adjustments of those amounts to facilitate computation and to avoid fractions of 1 cent in the amounts.