(a) Full registration periodA sex offender shall keep the registration current for the full registration period (excluding any time the sex offender is in custody or civilly committed) unless the offender is allowed a reduction under subsection (b). The full registration period is—
(b) Reduced period for clean record
(1) Clean recordThe full registration period shall be reduced as described in paragraph (3) for a sex offender who maintains a clean record for the period described in paragraph (2) by—
(D)
successfully completing of [1] an appropriate sex offender treatment program certified by a jurisdiction or by the Attorney General.
(2) PeriodIn the case of—
(A)
a tier I sex offender, the period during which the clean record shall be maintained is 10 years; and
(B)
a tier III sex offender adjudicated delinquent for the offense which required registration in a sex registry under this subchapter, the period during which the clean record shall be maintained is 25 years.
(3) ReductionIn the case of—
(B)
a tier III sex offender adjudicated delinquent, the reduction is from life to that period for which the clean record under paragraph (2) is maintained.