Google Contacts Sync

Google Contacts Sync

Hello,
I set up the Contacts Synch with Google Apps.

Select bi-direction sync.

Two question:

  1. I blank some value (es telephone number or email) from Zoho CRM, but in Google contacts I still keep the previous value. Seems that syncronization only work if I change a value, but if I blank the field it doesn't work
  2. From documentation I see that the key used for mapping contact is the email
    ((primary email field in contacts) in Zoho CRM and  Email (Work)  field value in Google Contacts). Anyway if I change the email from of a contact in zoho CRM that value change also in Google contacs and, in the other hand, if I add a new contact in ZohoCRM with an existing email, That create a new Google Contact with the same email of an exisiting contact. So the question is: Wich is the field that ZohoCRM and Google Contacts use for matching records?
Thanks

Matteo Da Rù