How is calculated each tax year the current income for the calculation of self-employed's advance payments?

​At the start of tax year, the income of the current year is calculated according to the following options:

• Based on tax return or self assessment for the closest tax year to the current one, received before January 1st of that year, and based priority rules.
• Based on advance payments modification, and provided that an income tax return for the year of the modification has not been received yet, and based on priority rules.
• If the insured does not work and the las tax return was made three years or more before the current year, and the National Insurance informed him of his obligation to file a report - the quarterly advance payment will be calculated based on a declaration.
• if a determination is made upon the insured - advance payments are established according to this determination.