EV Reports discrepancy

Hello all,

I have a discrepancy between two reports and I was hoping you could maybe shed some light on the issue for me. EV implementation being used for FSA only. The Vault store usage summary report shows a different number of total items (3779599) than the FSA: File Space Usage by File Group on a Specified File Server report shows (3798323) under the Number of Archived Files column. It's a large discrepancy.

Any ideas what might be causing this? 

Thanks,