(a) Except as provided in (b) of this section,
(1) computations of a 72-hour evaluation period under AS 47.30.715 or a 48-hour detention period under AS 47.30.685 do not include Saturdays, Sundays, legal holidays, or any period of time necessary to transport the respondent to the treatment facility;
(2) a 30-day commitment period expires at the end of the 30th day after the 72 hours following initial acceptance;
(3) a 90-day commitment period expires at the end of the 90th day after the expiration of a 30-day period of treatment;
(4) a 180-day commitment period expires at the end of the 180th day, after the expiration of a 90-day period of treatment or previous 180-day period, whichever is applicable.
(b) When a respondent has failed to appear or been absent through the respondent's own actions contrary to any order properly made or entered under AS 47.30.660 - 47.30.915, the relevant commitment period shall be extended for a period of time equal to the respondent's absence if written notice of absence is promptly provided to the respondent's attorney and guardian, if there is one, and if, within 24 hours after the respondent has returned to the evaluation or treatment facility, written notice of the corresponding extension and the reason for it is given to the respondent and the respondent's attorney and guardian, if any, and to the court.