Section 61(4)(b) in The West Bengal Correctional Services Act, 1992
(b)The provisions of this sub-section shall apply only in the case of conviction or commutation as aforesaid made after the 18th day of December, 1978 but shall not apply in the case of conviction by way of imprisonment for life, though made after the 18th day of December, 1978, is such conviction arises out of an appeal against the order of acquittal passed before the 18th day of December, 1978, by any trial Court.