There have been a lot of discussions on the same subject in this forum. I believe that if the PF qualifying salary is Rs. 15,000, then any loss of pay, being non-contributory days/periods, should be made on Rs. 15,000 proportionately. As such, if the PF salary is Rs. 15,000, in respect of an employee who joined on 2nd February, the salary for the purpose of PF should be the salary for one day less than Rs. 15,000, or Rs. 14,500, or Rs. 14,483 (for February).