Only 200 contacts are synced to the iPhone App when the download option is set to "My Assigned Contacts".
If an account manager has more than 200 people and this user logs into the iPhone and syncs just with "My assigned contacts" then only 200 people are synced to the iPhone.
Resolution / Workaround:
A workaround is to sync all the contacts to the iPhone.
This issue has been resolved in Sage CRM iPhone App version 2.0.4.