; or (II) may be not more than 90 days in a special housing unit if the inmate has previously been found guilty of a similar significant and serious disciplinary infraction; (C) ensure that any time spent in administrative segregation during an investigation into an alleged offense is credited as time served for a disciplinary segregation sentence; (D) ensure that concurrent sentences are imposed for disciplinary violations arising from the same episode; and (E) ensure that an inmate may be released from disciplinary segregation for good behavior before completing the term of the inmate, unless the inmate poses a substantial and immediate threat to the safety of other inmates, staff, or the public. (6) Special management units The Director shall— (A) limit segregation in a special management unit to situations in which such segregation is necessary to temporarily house an inmate whose history, behavior, or circumstances require enhanced management approaches that cannot be addressed through alternative housing; (B) evaluate whether further reductions to the minimum and maximum number of months an inmate may spend in a special management unit are appropriate on an annual basis; (C) ensure that each inmate understands the status of the inmate in the special management unit program and how the inmate may progress through the program; and (D) further reduce the minimum and maximum number of months an inmate may spend in a special management unit if the Director determines such reductions are appropriate after evaluations are performed under subparagraph (B). (7) Administrative maximum facilities The Director shall— (A) limit segregation in an administrative maximum facility to situations in which such segregation is necessary to— (i) implement special administrative measures, as directed by the Attorney General; or (ii) house an inmate who poses an ongoing significant and serious threat to the safety of other inmates, staff, or the public that cannot be addressed through alternative housing