Post office rd premature

If a person open RD in post office, he can withdraw from it (i.e. closed) after a period of 3 years.

Int on post office RD 7.5%

If premature, same as on post office saving bank i.e. 4%

Now, if RD is close than he received interest less as he planned & booked in his assessable in the previous year. Than what is the treatment for the interest which is booked in last yeay at high amount, but received less for the last year in the current year.

Now, whether exempltion wll be available on the interest which he received. Because interest on post office saving account is exempt to some extent, but interest on RD is not exempt