Ragnorock uses invoices, but he did OK though.  I think it also has something to with how old/new your account is, how much you have been receiving versus how much you have been paying, if you have a credit card or two as backup payment instruments, and if you have some regular activities (in or out).
Invoice could be a problem still.  I didn't use invoices for my acrylic cases, and some people gifted me money, some paid as goods payments.  BiNi also took in a lot of payments for Phantom group buy.  No invoices, some goods payments, some gifts.  I have had my paypal account for over 10 years.  Mostly for sending payments.