The official letter No. 2427/TCT-TNCN dated 30 July 2013 of GDT in guidance of pit polycy for income from service contract
According to official letter No.2427/TCT-TNCN:
If an individual signed long-term labor contracts with an enterprise, and in 2011, the individual also signed service contract (non-administration time) with this enterprise, the income from service contract will be subject to PIT with 10% tax rate (tax code) or 20% tax rate (without tax code) and not be added to the monthly wage, salary to calculate PIT by the partly progressive tariff. At the end of a year, the individual can ask the enterprise to finalize PIT of 2011 as regulations.