I believe your thought is correct, ie no siteworx account exist in your account
That said though, if you look at your reseller account, it shows as unlimited, so the screen your looking at displays Infiniti or 0 used
If we has limited your reseller account, you would see limit values shown, which would be 0 unless some had been used.
You can reset your own values using the credentials I emailed, and see what I mean, and create a siteworx account, populate it with some data (prefer 1gb of data) and it may make more sense I think.
If you want me to populate, please let me know