Understanding National Codes for Services
You use the Service National Codes program (P76B407) to set up the national codes that you use for ISS withholding. After you set up the national codes, you can associate them with service codes for cities. You obtain the national codes from the Brazilian government. The system stores the values that you enter in the National Code table (F76B407). Setting up national codes is an optional task; it does not affect the ISS calculations.
When you run the Tax Calculation ISS, INSS, FUNRURAL program (R76B4310) to calculate ISS taxes, the system saves the national code to the Withholding by City and Service Detail table (F76B415).