A decision on the assessment of insurance premiums may not be made on or after the day on which two years have elapsed, counting from the day following the first due date for payment of insurance premiums for the relevant fiscal year (meaning the due date for payment by which insurance premiums are to be paid or remitted pursuant to the provisions of this Act or a Prefectural or Municipal Ordinance based on this Act, and, in the case where it has become possible to impose insurance premiums after that due date, the day on which it has become possible to impose the insurance premiums; the same applies in the following paragraph).
A determination of assessment that reduces the amount of insurance premiums in the case where, after a determination of assessment of insurance premiums has been made, it becomes evident, due to grounds not attributable to the insured person, that adjustment is required in the relationship of application with the respective Acts on medical insurance concerning insured persons (meaning the Health Insurance Act, the Mariners Insurance Act, the National Public Officers Mutual Aid Association Act, the Local Public Officers, etc. Mutual Aid Association Act or the Private School Personnel Mutual Aid Association Act) may, notwithstanding the preceding paragraph, be made even on or after the day on which two years have elapsed from the day following the due date for payment of the first insurance premium for the fiscal year, until the day on which a period equivalent to the period found necessary for the adjustment has elapsed from the day following the due date for payment of the first insurance premium for that fiscal year.
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