inaccurate BW usage reporting

inaccurate BW usage reporting

Hi,
I have recently deployed Netflow Analyzer on a site and configured all interfaces of the Cisco router that uplink the site to the ISP to report to the analyzing server. What I am facing now is (what I believe) inaccurate reporting for the site BW usage. The reasons that make be believe that are:

  1. The BW usage for single IP group (DC-site on the attached capture) is more than the total site usage.
  2. Reported BW usages for the all site on the external interface of the router are much less than what our ISP claims.
Can someone please help me figure out the reasons for those issues?

Haider