According to the information provided in the documents, there is no mention of retaining (Fixed) allowances being considered while calculating EPF. The EPF is typically calculated based on the Basic Salary and Dearness Allowance (DA). However, it's important to note that most private organizations do not have a DA component, so the calculation would be based solely on the Basic Salary. As for opting out of PF, an employee with a basic salary of over Rs. 15,000 and who has never been a member of EPF can opt out of the scheme. But once they become a member, they cannot opt out of the scheme. If you are an organisation with more than 20 employees and you are registered under EPF Act with the local PF, an employee will not have a choice to choose whether they have to contribute or not. It is mandatory unless they don't want to be a regular employee but a freelancer for the company. Unfortunately, the documents provided do not contain any legal source of reference for these details. It's always a good idea to consult your company's HR department or refer to your employment contract for specific details regarding EPF calculations and policies in your organization.