Clubbing of income of major child

So far I have been clubbing, under Section 64(1A), the interest income from my minor son's SB account and Bank FDs. Now he has become major, but he continues to be student, with no income of his own. Which section should I follow?

So far I have been taking an exemption of Rs. 1,500 while clubbing. Is it possible to avail full amount (max Rs. 10000) under section 80 TTA for his SB account (in addition to the deduction for my SB account).

Thanks & Regards.