With the launch of Payment Center, it is no longer possible to add a payment method by the name of "PayPal" to your list of displayed payment methods. Formerly this was possible as a means to allow merchants to select PayPal as a payment method in the older versions of checkout managed through the Order Forms link.
With Checkout Manager, and the integration of PayPal Express Checkout, merchants can now easily elect to display PayPal to buyers in checkout. Learn more.