I would also make sure they realize if they opt to sign up for half days they do NOT have the option of suddenly deciding they want full days and they cannot just occasionally want a full day.

If you plan to take on a before school and after school child then their spot is limited, and remains limited to the 8:30-12:20 time slot.

I would make this known and have them sign to that. They may decide it is in their benefit to pay for the full time spots to have flexibility to change back to full time when needed.