; (2) by striking paragraphs (1) and (4); (3) by renumbering paragraph (2) as paragraph (1), and paragraph (3) as paragraph (2); (4) by inserting or at the end of paragraph (2); and (5) by striking or at the end of paragraph (3). (b) Removing substance-Related violations as grounds for mandatory revocation of probation Section 3565(b) of title 18, United States Code, is amended— (1) in the flush text following paragraph (4), by striking revoke the sentence of probation and resentence the defendant under subchapter A to a sentence that includes a term of imprisonment and inserting revoke the sentence of probation and require the defendant to serve a term of imprisonment not to exceed 60 days unless otherwise authorized under subsection (a) or (d) ; (2) by striking paragraphs (1) and (4); (3) by renumbering paragraph (2) as paragraph (1), and paragraph (3) as paragraph (2); (4) by inserting or at the end of paragraph (1); and (5) by striking or at the end of paragraph (2). F Maximizing Public Safety Returns on Corrections Dollars 612. Clarification or original congressional intent regarding calculation of good time conduct credit (a) In general Section 3624(b) of title 18, United States Code, is amended— (1) so that paragraph (1) reads as follows: (1) Subject to paragraph (2) and in addition to the time actually served by the prisoner and any credit provided to the prisoner under any other provision of law, a prisoner who is serving a term of imprisonment of more than 1 year, other than a term of imprisonment for the duration of the prisoner’s life, shall receive credit computed under this paragraph toward that prisoner’s term of imprisonment. The credit under this paragraph is computed beginning on the date on which the sentence of the prisoner commences, at the rate of 54 days per year of the sentence imposed by the court, if the Director of the Bureau of Prisons determines that the prisoner has displayed exemplary compliance with institutional disciplinary regulations.