In computing any period prescribed or allowed by this chapter:
1. If the period begins to run on the occurrence of an act or event, the day on which the act or event begins is excluded from the computation.
2. The last day of the period is included in the computation, except that if the last day falls on a Saturday, Sunday, legal holiday or holiday proclaimed by the Governor or on a day on which the office of the Commission is not open for the conduct of business, the period is extended to the close of business on the next business day.