Waldorf is not year round.
Waldorf is a big believer in breaks for children which allows the knowledge they have learned to lie fallow and sink in. It is also why they cover subjects in blocks rather than once a week. In other words, in main lesson in 2nd grade, the children cover reading for 8 weeks, then they cover math for 8 weeks, then they go back to reading. They do however, continue free reading in the afternoons so they keep their practice up. Also, the areas they cover in the subjects changes. In math this year they did mulitiplication in the fall and division after Christmas.
The schools fiscal year begins on Aug 1 so the families start making payments in August for the school year that begins in September. You have the choice of paying all at once in August for the entire year (you get a 2% break if you do that), paying over 10 months or paying over 12 months. If you pay with a credit card, it is more to cover the credit card fee the school has to pay. So, whatever works best for your budget is how you pay.