Reductions of the probationary period required for the granting of conditional release may be granted to persons sentenced to life imprisonment in the forms and conditions provided for in Article 721; the total duration of these reductions may not, however, exceed, per year of imprisonment, twenty days or one month depending on whether or not the offender is in a state of legal recidivism. Reductions may, where applicable, only be deducted from the part of the sentence exceeding the security period provided for by Article 132-23 of the Criminal Code.