There is nothing wrong with finance.
Labor remuneration is different from wages and salaries.
If you are their employee, then there is an allowance. You don't have to pay taxes when you reach a certain amount, and the excess is paid at a progressive tax rate.
If it is labor remuneration, if it is less than 4,000 yuan, 800 yuan will be deducted and the rest will be paid 20%.
If it is more than 4000, deduct 20% and pay 20% for the remaining 80%.
If the one-time income is abnormally high, the tax will be increased by 50% and 10% respectively according to different degrees.
This can be found in the personal income tax law.