Hello Vishwanath,
The Age of retirement is not the same everywhere. It differ from central government to state govt. It also differ from different sectors and employment. And companies also have their own retirement policies......
Since PF is deducted on Basic pay, it applicable till the retiring person's last drawn salary, i.e 12% of last drawn basic pay.
The income tax for senior and very senior and very very senior citizens age is provided in order to give them the benefit of tax reductions. The percentage of Tax differ from different age groups , so it has got no direct connection with the PF deductions.......
Infact, if you take the government employees, their pension is fixed upon there last drawn salaries itself, say if u r retired in the month of may and u got the hike in the month of may itself or in previous month, the increased salary is taken in to consideration for the the pensions amount, so the last drawn salary is always considered for the final settlements......
(May observe the Tax Slabs :
Income tax slab 2012-2013 | financeminister.in
The main reasons behind such tax variations is for the cost of maintenance is high like medical expenses, dependency, and the salary they used to get when they were retired was meager in India....)