(2)For a convict-overseer, that -(a)he has served as a convict-watchman for not less than three months;(b)he has, at the time of his appointment earned three-fourth of the remission which it was possible for him to obtain;(c)he has served half his sentence;(d)his work as a watchman has given satisfaction; and that(e)he has a fixed abode.Explanation. - The uncommuted substantive sentence of a life prisoner convicted after the 1st September, 1939 who was eligible and might have volunteered for deportation shall be taken as 14 years for the purpose of promotion to the rank of convict night watchman and convict overseer.