To turn it off you need to update all of the server behaviors that communicate with paypal.
There should be one on the checkout page, one on the confirm page, and two on the pp_confirm page. If you open those server behaviors you can uncheck the sandbox option and update to add your live account information.
I got as far as "eCart LocalCheckout (Cart, PP_DirectPayment)" on the CONFIRM page and turning sandbox from true to false, but when I got to the panel that says "allow express checkout" I cannot turn it off (it is greyed out and on) and while I can uncheck sandbox, it will not let me save the changes, because it asks for username and other fields with asterisks. I want to uncheck express payments. Also, I don't see any other pp server behaviors on that page...