Yes, all orders under the same account (email) AND shipping address will be automatically combined and shipping overages refunded.
If you placed multiple orders using different accounts, your orders will NOT be automatically combined. You will need to leave a note on your order before check-out, or contact us using the "Contact" button at the bottom of the page.
If you do not wish to have your orders combined, please leave a note on your order before check-out, or contact us before the order has been shipped.