Traffic Report mismatch

We Tried Netflow analyser EE on our Internet GW Router. However we got a traffic data mismatch on Application Report.
In Application Report for 2 Weeks: Total traffic 31899 MB
smtp 12716 MB 40%
domain 9572 MB 30%
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However, when cliked on each application protocol (SMTP or Domain) to see the detailed traffic usage, traffic volumes are much lower than its aggregate value.
For eg. when double clicked, Domain traffic, its Total traffic volume shows as 735 MB
Source IP Destination IP Application Traffic (735 MB)
203.... 203. Domain 619 MB
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We cant decide which figure shows correct traffic volume(In this case for domain traffic, whether it is 9 572 MB or 735 MB )
Any clarifications on this pl..?