The Payout transfer indication is due to the fact that any royalty or fee will be applied to those contracts only. Since ERC-721 is unique the protocol will never try to extract fees /royalties from the NFT payout. Given the scenario that an exchange between two different NFTs is made royalties or fees are not applied. Also, there is a priority order for the fee to be applied (it's only applied to one side of the transaction) which will go first to Native Blockchain Token, then to ERC-20, and finally to ERC-1155.