What are the rules regarding Payment and Interest under Negitiable Instrument Act?

Payment and Interest under Negitiable Instrument Act says:

(a) To whom payment should be made (Section 78): Payment of the amount due on promissory note, bill of exchange or cheque must, in order to discharge that maker or acceptor, be made to the holder. If payment is made to any person other than the holder, the holder can claim payment over again from the maker or acceptor.

(b) Payment of interest when rate is specified (Section 49): Where interest at a specified rate is expressly made payable on a promissory note or a bill of exchange, interest shall be calculated at the rate specified, on the amount of the principal money due thereon; (i) from the date of the instrument until tender or realization of such amount (ii) from the date of the instrument until such a date after the institution of a suit to recover the principal amount as the Court directs.

(c) Payment of interest when no rate is specified (Section 80): When no rate interest is specified in the instrument , interest on the amount due shall be calculated at the rate of 18% per annum from the date at which the instrument ought to have been paid until tender or realization of the amount, or until such date as the Court directs.