A.Time Calculations. In computing any period of time prescribed or allowed by these rules or by order of the Board, the day 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, a Sunday, or a legal holiday, in which event the period runs until the end of the next day which is not a Saturday, a Sunday, or a legal holiday. Where the time period within which an action must be taken is specified by statue, the terms of the statute will control and the provisions of this paragraph will not apply.B.Enlargement of Time. When by these rules or by a notice or order issued by the Board, an act is required or allowed to be done at, before, or within a specified time, the Board for good cause shown may, at any time, at its discretion, with or without request, motion or notice, order the period enlarged before the expiration of the period originally prescribed or extended by previous order, provided that time limits or periods that apply to other persons affected by the resulting change or delay are also adjusted appropriately.Requests for enlargement of time which are filed after expiration of the period originally prescribed or as extended by previous order will be granted only in exceptional circumstances.95- 629 C.M.R. ch. 4, § 5