I think I've seen this before where Etsy considers each item purchased to be an order. For example - if a customer orders two things, Etsy will display it has 2 orders when it is really one order from one customer. Unless the customer made two separate purchases in your shop. Then that is a totally different thing.
When you click on "Sold Order," you'll see your open orders - then click on the "receipt #" and that should allow you to view the entire order. You can print your label from there and mark both items as shipped if going to the same address. I would definitely place them in the same box to save on shipping. Not sure if there is a way to refund part of the shipping money back thru DC. But if you are uncertain about combining the shipping, you can always ask the customer if they want it in the same box.
Hope that helps and it wasn't too confusing ;o)