In computing any period of time prescribed by or allowed by the
regulations contained in part 458 of this subchapter, the day of the
act, event, or default after which the designated period of time begins
to run, shall not be included. The last day of the period so computed is
to be included unless it is a Saturday, Sunday or Federal legal holiday
in which event the period shall run until the end of the next day which
is neither a Saturday, Sunday, or a Federal legal holiday. When the
period of time prescribed or allowed is seven (7) days or less,
intermediate Saturdays, Sundays, and Federal legal holidays shall be
excluded from the computations. When these regulations require the
filing of any paper, such document must be received by the Assistant
Secretary or the officer or agent designated to receive such matter
before the close of business of the last day of the time limit, if any,
for such filing or extension of time that may have been granted.