Could These Ideas Save Local Schools Money?

I spent last weekend in the Boston area at a bat mitzvah and seeing my family. My sister's children go to a public school system that--size-wise and demographically--looks a lot like the Ann Arbor school system. I heard about two things that this school system does that might be worth implementing locally.

1. For elementary school children, Tuesdays are an early dismissal day (12 or 12:30, I don't remember). For teachers, Tuesday afternoons are time for planning meetings and professional development. Professional development days are not scheduled throughout the year, and local child care settings (including the public school's own) are set up to accommodate the short Tuesday. That would seem to simplify things for parents. Would it also save money? Sometimes subs are hired for planning or professional development.

2. In the elementary and middle schools, substitute teachers are called on for both short-term and long-term assignments, as they are here. But in the high school, it's a different ball game. The only subs there are long-term subs. If a teacher wakes up with a sore throat, she or he calls in sick, but no substitute is called, no emergency lesson plan called upon. For the students, that class is cancelled. Instead, students go to study hall. The study hall is a large room (fits about 100), supervised by one teacher (teachers apparently take turns like you would for lunch duty). Overflow goes into the commons (although I believe that 11th and 12th graders are allowed to leave campus). My niece tells me a class is cancelled for her approximately once a week, and she likes it because it gives her extra study time.
Think about it--how much do substitute teachers, there for 1-2 days, actually teach? Based on my experience as a high school sub, precious little.
The cost savings, I would imagine, are pretty significant.