Understanding Email notication

I am struggling to understand the Email notication in netbackup.  It seems there are at least 3 places in the NBU GUI, NetBackup Management section:
 

1. Host Properties > Master Server > Server_hostname > Global Attributes  > Administrator’s email
2. Host Properties > Master Server > Server_hostname > Universal Settings > Client administrator’s email
3. Host Properties > Clients       > Client_hostname > Universal Settings > Client administrator’s email

Suppose I have servers administered by the following teams:
 

NBU Master: Adminstrator: TEAM NBU
hostX: Adminstrator: TEAM App A
hostY: Adminstrator: TEAM App B
hostZ: Adminstrator: TEAM App B

So as I understand I could use:
 

email method 1 (Master Server Global Attributes) as "TEAM NBU" so that TEAM NBU gets Email notications for all backups 

email method 3 (Clients Universal Settings) as "TEAM A" for client hostX and "TEAM B" for clients hostY and hostZ, so that TEAM A/B only get emails for the hosts they administer
 

So my questions are:

1. Is my above understanding correct
    
2. What do I use email Method 2 for and how is it different from Method 1
    
3. In the manual it says Method 1 and 2 only send emails for unsuccessful backups and Method 3 sends emails for ALL backups - is this correct and if so why is there this difference and why is it not apparent in GUI (i.e there is nothing in GUI that signifies that the exit code of the backup has any bearing on whether email are sent out or not)

Thanks

Mike