The calculation of any time period measured in days by Finance Code Chapter 159 is to be made using calendar days. In computing a period of days, the first day is excluded and the last day is included. Except with respect to the disclosure required by Finance Code § 159.101 and § 78.101 of this title (relating to Required Disclosure), if the last day of any period is a Saturday, Sunday, or legal holiday, the period is extended to include the next day that is not a Saturday, Sunday, or legal holiday.
7 Tex. Admin. Code § 78.3