13. If I claim old-age pension 3 years in advance, and after I have gotten 3 years of old-age pension at 60 years old, Could I change to claim full amount of old-age pension without the deduction?
No. If you claim old-age pension in advance, the deduction will not be changed again. Therefore after you turn 60, the amount you receive every month for old-age pension is still the amount after the pension advancement deduction.