You or Enhance can only control to some extent what is related to your server (local). You can call it Total Control, and you are limited from hardware and software configs, but once the *gz is created and you send to whatever location, once data is leaving your server network port from there, you have nearly 0% control, and everything has to do with ISP peering and route data takes from your server to storage server. And no one can really do much about it.
You might think location should be relevant, but sometimes, even if you have a close backup storage, there might be times when busy neighbours would make your real available bandwidth very limited.
There are also, on the route data takes, "software limitations" imposed by the ISPs per connection; you could achieve faster speeds if concurrent connections, but each connection is limited to xx Mbps.
From what you are saying, I would say the last scenario is your case.
