How good the model is if the C-score is -2.33 ?

In the nature protocol paper, C-score >-1.5 is considered as good prediction. How about C-score -2.33? The corresponding TM score is 0.44+/- 0.14. So does it mean it is better than a random guess but still a suboptimal model?
Do you have any false positive and negative rate for any given c-score?
Thank you very much!