Hi Divya,
Pf calculation is 12% on Basic , DA, Other Allowance (in rare cases) not on the Employee Gross.
for the Fixed PF deduction for every employee you need to create a PCR and insert in the Schema INAL - period factoring and storing after the line PIT X023 with function PIT.
before doing any changes first consult the PF authority and take their approval.
i have one more doubt if fixed PF and other deductions are more than Employee Earnings then what is the solution. if this PF fixed is through out all the positions in the company.