Once again I am using the file section. I am not talking about mail usage
The maximum file size you are referring to is in the web interface. I am using FTP with Transmit limited to 1 connection to server (as the documentation says).
With an upload speed of 50kb I am nowhere close to reach any of the bandwidth limits. And the worst thing is that even though I just leave it so it can take it's time 8 out of 10 times the upload fails anyway.
To upload one file with a size of 2-400 mb is *not* heavy cloud storage usage