Last August we used 2 snack credits for a chocolate muffin and a package of 2 Krispy Kreme donuts. They asked if we were using CS or snack credits, so I assume they would have let us add a drink and use a CS, if we wanted, though it sounds like their policy may have changed. Which may change our plans--my kids would love to get the 2 sweets + drink for a CS, but 1 sweet + 1 savory + drink is not as appetizing to them. So we may stick with the snack credits at the MSB and save the CS's for lunch.
Good luck!