[E2013] [EWS] De-Duplication feature in eDiscovery

Hi,

I would like to know about the functionality of the deduplication feature provided in E2013 EWS. 

Under the following scenario how does it work?

I have a mailbox under In-Place hold where i have the De-duplication set as True. I send a mail matching hold criteria to that account and forward the same message to the same account. 

Thanks