While there is an IP or Email score greater than 0, the amount is not added to the total of the Fraud score, how is this possible?

By modifying the IP or Email weight under the Setting option of your account the score will be increased or decreased respectively. 

The scores from the applied rules will be presented on the IP or Email widget with unmodified scores, however in the overall fraud score the altered amount will be added.

For example, the Email weight is set to 200% and a rule that would add a score of 5, the original value of 5 will be present on the Email widget, while the fraud score will be increased by a score of 10.