Ppf investment

Hi,

PPF allows investment upto 1Lakh (max) in one financial for interest calc but voluntary addition of amount is not restricted to 1lakh. So does this mean that the amount added >1Lakh will be used as base/balance amount for next yr calc?

Eg. In 2012 invested 2 Lakh in PPF. So interest will be calc for 1Lakh per say 8.8%. So in 2013 the balance amount in PPF will be 208800 (2Lakh + 8800Rs interest)  and interest of 18374Rs (8.8% of 208800) will be credited for 2013?

Thanks