Section 21(1)(iii) in The Karnataka Money-Lenders Act, 1961
(iii)all payments credited first in the account of interest and the residue, if any, of any payment more than sufficient to discharge the balance of interest due at the time it is made, credited to the debtor in the account of principal, in the alternative such of the payments credited first in the account of principal as the money-lender may determine and the remaining payments credited in the account of interest calculated on the basis of the decreased balance of principal and when the balance of interest is fully discharged the residue of the payments, if any, further credited in the account of principal;