When you edit your delivery, at the top, you can see the number of credits allotted to your delivery according to your plan size.
Each individual grocery item and recipe is assigned a credit value, and you can fill your box until the credit value has been reached.
For example: if you’ve got 33 credits, you could add three 9 credit recipes and still have 6 credits left to get snacks or other individual items. Or, you can add more beyond your allotted credits! You can spend them any way you’d like.