NFA is showing data far less than expected. For example data may be displayed as 1/10th, 1/100th, 1/1000th of what SNMP Statistics show.
For example a report may be showing data rates in the kbps range when it should be in the mbps range.
This can occur when a router is using a Sampling Rate when sending Netflow, meaning it sends 1 out of every x number of flows. If NFA does't detect the sampling rate properly, data will be displayed as far less then expected. Later Cisco IOS version adjusting their sampling rate format so that it was not detected by NFA.
NFA 9.3.6 and Later
update routing_engines set samplerateoverride=1000 where routerid in(select routerid from routers where inet6_ntoa(router)='10.1.1.1');