Authorizing an individual who is at least 60 years old and has been imprisoned for at least 20 years to file a motion to reduce the duration of the individual's sentence; requiring the court to conduct a hearing on a motion to reduce the duration of a sentence, unless the court has held a hearing on a similar motion in the preceding 5 years; and requiring a court to consider enumerated factors in determining whether to grant a motion to reduce the duration of a sentence and to issue its decision in writing or on the record in open court.