D.__Regional school calendars may have provisions for waivers of the number of dissimilar days for extenuating circumstances.

E.__Plans for regional school calendars must be approved and implemented in time for the 2005-2006 school year.

The commissioner shall adopt rules to establish requirements for regional school calendars.__Rules adopted pursuant to this subsection are major substantive rules pursuant to Title 5, chapter 375, subchapter 2-A.