No, the vendor does not enter their payment address in the payout settings. The vendor accumulates balance and then they are free to perform a withdrawal at any time using the plugin to an address that they choose.
You could buy membership to download the plugin, and if in the next 30 days you decide that the plugin is not for you, you can request a refund. It’s in the terms of service.
I would recommend that you first make sure that you are happy with the parent plugin, Bitcoin and Altcoin Wallets. This is the free part of the plugin. No point in buying the extension if the parent plugin is not to your liking.
with regards