(a) In computing any period of time provided for by this part, or any order issued pursuant to this part, the time begins with the day following the act, event, or default, and includes the last day of the period, unless it is a Saturday, Sunday, or legal holiday observed by the Federal Government, in which event it includes the next business day.

(b) When the applicable period of time is less than seven days, intermediate Saturdays, Sundays, and legal holidays observed by the Federal Government shall be excluded from the computation.