Correct, Sunsail prices all charters with a evening start. The Moorings prices charters with a noon start and you add the sleepaboard night if you want it. Sunsail has been that way since long before the Moorings purchased them. Why I don't know. It is reflected in the pricing. A 7 night charter with Sunsail is a sleepaboard with 6 nights out on the water.
Keep in mind that pricing is negotiable. A sleepaboard is sometimes a item you can get discounted or free.
G