269ss/t

Yes interest is also included while considering the threshold of 20k.  refer the provision of 269T below:

269T. No branch of a banking company or a co-operative bank and no other company or co-operative society and no firm or other person shall repay any loan or deposit made with it otherwise than by an account payee cheque or account payee bank draft drawn in the name of the person who has made the loan or deposit if—

(a)  the amount of the loan or deposit together with the interest, if any, payable thereon, or

(b)  the aggregate amount of the loans or deposits held by such person with the branch of the banking company or co-operative bank or, as the case may be, the other company or co-operative society or the firm, or other person either in his own name or jointly with any other person on the date of such repayment together with the interest, if any, payable on such loans or deposits,

is twenty thousand rupees or more