Sec.  65.15  Calculation  of  periods of probation and of conditional
     discharge.
   1.  A  period  of  probation  or  a  period  or  additional period of
conditional discharge commences on  the  day  it  is  imposed.  Multiple
periods,  whether  imposed  at the same or at different times, shall run
concurrently.
   2.  When  a  person  has  violated the conditions of his probation or
conditional discharge and is  declared  delinquent  by  the  court,  the
declaration of delinquency shall interrupt the period of the sentence as
of the date of the delinquency  and  such  interruption  shall  continue
until  a  final determination as to the delinquency has been made by the
court pursuant to a hearing held in accordance with  the  provisions  of
the criminal procedure law.
   *  3. In any case where a person who is under a sentence of probation
or  of  conditional  discharge  is  also  under  an   indeterminate   or
determinate  sentence of imprisonment, imposed for some other offense by
a court of this state the service of the sentence of imprisonment  shall
satisfy the sentence of probation or of conditional discharge unless the
sentence of probation or of conditional discharge is  revoked  prior  to
the   next   to  occur  of  parole  or  conditional  release  under,  or
satisfaction of, the sentence of imprisonment. Provided,  however,  that
the  service of an indeterminate or determinate sentence of imprisonment
shall not satisfy a sentence of probation if the sentence  of  probation
was  imposed at a time when the sentence of imprisonment had one year or
less to run.
* NB Effective until 2005/09/30
   *  3. In any case where a person who is under a sentence of probation
or of conditional discharge is also under an indeterminate  sentence  of
imprisonment,  or  a  reformatory sentence of imprisonment authorized by
section 75.00, imposed for some other offense by a court of  this  state
the  service  of the sentence of imprisonment shall satisfy the sentence
of  probation  or  of  conditional  discharge  unless  the  sentence  of
probation  or  of  conditional discharge is revoked prior to the next to
occur of parole or conditional release under, or  satisfaction  of,  the
sentence  of  imprisonment.  Provided,  however,  that the service of an
indeterminate or  a  reformatory  sentence  of  imprisonment  shall  not
satisfy a sentence of probation if the sentence of probation was imposed
at a time when the sentence of imprisonment had one year or less to run.
* NB Effective 2005/09/30

(For verification consult Official Text at Senate Gopher site.)