Question about contact synchronization to Outlook 2011 for Macintosh MAC OS X Lion.

Exchange Server

- On the Exchange server contacts are listed as 12k+
- When downloaded to any Microsoft e-mail program this number is exact

- When downloaded to any of the Macintosh mail programs such as Entourage EWS, Outlook 2011 and v5 the number is halved.

- Does EWS not download Duplicates?
- How does EWS or these programs distinguish contacts?
- What contact entrees will not download?

Any assistance is greatly appreciated.