Computation of time

Computation of any period of time referred to in these rules begins with the first day following that on which the act which initiates such period of time occurs. The last day of the period so computed is to be included unless it is a day on which the office of the commission is closed, in which event the period shall run until the end of the next following business day. When such period of time, with the intervening Saturdays, Sundays and legal holidays counted, is five (5) days or less, the said Saturdays, Sundays and legal holidays shall be excluded from the computation; otherwise such days shall be included in the computation.