Sounds like you are using an older LW 5 version. Have you tried updating to LW 5.2? With LW 5.2 you can set downloads to over 10 from memory.
The limit of downloads might be related to simply luck of connecting to the hosts. Often wise to re-search your original search terms & then do a Find More Results search. This will hopefully find more hosts to connect to.

If the files are torrent files .. then that can be more to do with luck.