such implementation error is corrected not later than—
(I)#
the date of the first payment of compensation made by the employer to the employee on or after the last day of the 9½ month-period after the end of the plan year during which such error with respect to the employee first occurred, or
(II)#
if earlier in the case of an employee who notifies the plan sponsor of such error, the date of the first payment of compensation made by the employer to the employee on or after the last day of the month following the month in which such notification was made,