(2) the amount by which the maximum insurable earnings for the year exceed the quotient obtained by dividing the aggregate of the following amounts by the premium rate referred to in subparagraph 1 of the first paragraph of section 6:(a) the total deductions at source from the worker’s or resource’s wages for the year as an employee under this chapter, reduced, if applicable, by the premium overpayment established in accordance with the first paragraph of section 68;
(b) the premium the worker or resource is required to pay for the year under section 64, determined without reference to section 65.