Reconciliation between AP Aged Report and General Ledger

NAV version 5.0SP1 - The balance shown by the AP Aged Report (native, Aged as of 12/31/13 by Document Date) for a particular project code does not match with the GL account balance for the same date (..12/31/13) for the same project code. I tried running the AP Aged report by both Trans Date and Document Date and the result is the same.

There are no entries posted directly to the GL AP account without going through the AP sub ledger. There are some Vendor ledger entries where the document date is in 2014 with the posting date in 2013. I understand that could cause a difference but even after accounting for those, there is still a big difference. Is there any other factor that could cause this?

Thanks

Kind Regards,

-Vasu