Wan Link Load Balancing

Hi All

  Right now we have HA Fortigate 3950B with firmware version 5.2 connected to 3 ISPs. We use Wan Link Load balancing to bundle 3 Port to ISPs. Since we bundle 3 port ISPs to load balancing why i can't add widget interface history for that wan load balancing to monitor traffic history from that bundle interface? 

Thx