File permissions while sending the file from one Linux host to another host

One of the source servers is sending the files to destination servers using lftp. The umask setting in the destination host is 007(in proftpd.conf file), so the files landing in the destination servers should be 660(007-666), but the permissions are varying. What could be the factors contributing to the permissions of the files while transferring from one host to another using lftp?