It sounds like then they are counting connections by hostname rather that by user as should likely be the case.
The real solution here is to get away from using ftp, but yes I do realize that even currently manufactured low-cost NVR’s don’t offer a choice of anything other than ftp. Because of this, it’s best to implement a low cost “middle-man”. A Raspberry Pi (even a PI Zero would work for this) does nicely. Put it behind a local router(firewall) so you don’t need to concentrate on keeping it’s software up to date, with no incoming path ( Internet --> PI ) there is little security concern. Set up the NVR to ftp (locally) to the PI, run a script on the PI that watches a directory for new files and when it finds them SFTP’s them to the dreamhost server.
It’s reliable. I’ve set the above up for someone else (different host, but same issue), the PI has been running 372 days now without being touched. It ran 6 months before that and I don’t know exactly why it stopped at that point, because someone rebooted the PI before I got to see it’s state.