as you know in ftp protocol client sends PORT or PASV before it actually tells server what it's going to do with it.
so if server doesn't allow PORT command with ip other than your own, it will refuse that action no matter if next command is going to be uploading or downloading...
with PASV command server won't know who will connect to it untill after you tell it about uploads or downloads, but still as soon as it sees that somebody else other than you are trying to connect to it, it might refuse that connection.
so in other words from server's point of view there is pretty much no difference if it's being FXP to or from.
granted some more advanced servers might have dedicated settings to explicitly allow/deny incoming/outgoing FXP tranfers, but then you wouldn't have this question