Great info @followthecoin!; i too searched the white paper for a better understanding of the meaning of the terms on the transparency page; but it seems a clear definition is lacking..
Your information is really helpful and i appreciate you sharing with the community :).

I am adding a picture of your tweet as it add's clarity to the story
as linked above [https://twitter.com/FollowTheChain/status/742373658019012608]

(https://twitter.com/FollowTheChain/status/742373658019012608)

Seems like there is definitely something suspicious about this; as mentioned above Tether have remove the minus sign to presumably make is less visible that they are under their collateral requirements.