To determine the amount of tax to be withheld, the employer shall use either the tables or formula method provided by the department.
If the payroll period is a multiple of one week, other than biweekly, the employer shall determine the amount of tax to be withheld as follows:
If wages are paid on a quarterly, semiannual, or annual basis, the employer shall compute the amount of tax to be withheld by multiplying the average wage for one month by the number of months in the payroll period.
Haw. Code R. § 18-235-61-06