I do not think anything about any financial institution, that's why I mentioned "technically" what should be and asked OP to confirm with BoB
I am not aware of 50p case, but if that 50p was after 3 days grace period, customer can not even fight legally and can only request. Its upto BoB to accept it or not.
But, in this scenario, assuming OP is correct in the calculation of 3 days, he can fight legally and drag BoB to RBI if they do not comply.