So I graduated from university on March and chose to work parttime for the company, which I had contract with and would start fulltime at April.
They had this rule that parttime work is paied next month's 25th so in April I recived my April salary + parttime hours from March.
This month I found out that my social contributions 社会保険 will be defined depending on the median income for months April – June. And receiving this parttime payment in April basically made me move to the next bracket paying extra for the rest of the year, even though the rise in income was only for one month and it was for working during March.
If I new this beforehand I would worked fewer hours for the same payment during March.
by Sad_But_Glad