(a) In computing any period of time prescribed or allowed by the
rules of this part, the date of the act, event, or default after which
the designated period of time begins to run, is not to be included. The
last day of the period so computed is to be included, unless it is a
Saturday, Sunday or a Federal legal holiday, in which event the period
runs until the end of the next day which is neither a Saturday, Sunday
nor a Federal legal holiday. When the period of time prescribed, or
allowed, is less than 7 days, intermediate Saturdays, Sundays and
holidays shall be excluded from the computations. Whenever a party has
the right or is required to do some act or take some other proceedings
within a prescribed period after service of a notice or other paper upon
the Secretary or a party and the notice is served upon him by mail, 3
days shall be added to the prescribed period: Provided, however, That 3
days shall not be added if any extension of such time may have been
granted.
(b) When these rules require the filing of any paper, such document
must be received by the Secretary or a party 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.