Please note that once the EPF Act is made applicable to the main unit, it automatically applies to all units across India. The question of independent coverage of a branch of an EPF-covered main unit does not arise. However, for the sake of administrative convenience, you can apply for a PF Sub-Code Number for your branches if they are located in different parts of India. The question of having 20 employees for each branch for the purpose of the application of the EPF Act does not arise.
The same principle applies to ESI as well. However, if the branch is located in a "Non-Implemented Area," the applicability of the ESI Act to the branch does not arise as it is situated in a Non-Implemented area.