First I’m surprised not found a Storj DCS sub-forum where your customer could exchange.
Otherwise I’m a free tester. I noticed after downloading 4.38GB from the web interface, the dashboard bandwidth show a 6.35G usage and the bucket bandwidth show 6.05GB, both were at 0 before the download. A 45% over-billing might upset some customers.
It took 19.5 minutes to download 4.38GB or 13.5 GB/h, 323 GB/day. It would take me 3 days to restore my 1Tb SSD and 3 weeks to restore my HDD, not very appealing for data backup.
For information I’m in France with a 1000/500Mb fiber.