When you spend the balance on your paper wallet (for example by sweeping the private key into your blockchain.info wallet), anything that is not spent is sent as change to an address in your blockchain.info wallet. This won't be the same address as the address of your paper wallet. So you'll have to decide what to do with the change-funds. You can either keep them in your blockchain.info wallet or create a new paper wallet where you transfer the remaining funds to.
How do you choose your change address?