Why is traffic graph not showing correct figures when using access points

[tripplex]

I have pfsense 2.3.2 with triple wan 20mbps load balancing. I have 3 access points connected to a cisco workgroup switch from my 100mbit lan port on the pfsense box. The problem when I run a speed test or have heavy traffic loads on the access points the traffic graphs don't reflect the usage. Why is that?

[Nullity]

Are you selecting the appropriate interface in the traffic graph?

[tripplex]

yes i selected all the wan connections i have but when the usage is high it doesn't reflect it.

[tripplex]

still having issues with this and i have upgraded my system. Have hp nc364t quad port nic and still facing the same issue.
during the evenings when the load is high it still doesn't show the correct figures on traffic graphs.

I have 3 x 20mbps bandwidth from isp and when the load is high, the highest one of the wan goes is 7mbps.