Good points and Demerit against ceiling of annual earnings

Demerit:

In case you have to enroll the social insurance and national pension、your net income for the year might be reduced.

Good points:

However on the another hand, you may be able to receive more pension for the years after 65-age. For social insurance, you may be entitled to receive Injury and sickness allowance「傷病手当金」and/or maternity allowance  「出産手当金」、when you have such injury and sickness leave, and maternity leave.

This is the right time for you to consider your future thru this change of tax.