When performing the same search against the same archives, the Clearwell Enterprise Vault (EV) will discover less items than Discovery Accelerator.
Clearwell uses a matching FROM/RECP set of attributes to search while Discovery Accelerator uses NAME (which converts to AUTH/RECP).
The FROM attribute will not search the message envelope (MsgEnv); only the Sender Recipient list (SeRe). AUTH (Author) will search the MsgEnv as well as the Sender Recipient list.
This issue has been resolved in version 7.1.2 FIX2