Understanding License Limit Exceeded Exception in e-Messaging

Count of email in the system is incremented on either of following events:
•        An outbound email is sent by eMessaging. Total number of such emails can be known by the count of occurrence of 'Mail Sending process complete' for that month in eMessaging Application logs
•        An Inbound email is received which is NOT 'bounced' or 'Out of office' (OOO) notification corresponding to an outbound message sent by eMessaging. Total number of such emails can be known by occurrence of "Incrementing license count if message is not outofoffice or bounced"

Count of emails of each Month & Year can also be known by executing below query in the e-Messaging database:
Hosted on SQL Server:
Select COUNT(*)  "Email Count", DATEPART ( YEAR , date_send ) as "Year"  ,DATEPART ( MONTH , date_send ) AS "Month" FROM [outbound_message]
group by DATEPART ( YEAR , date_send ),DATEPART ( MONTH , date_send )
Hosted on Oracle:
SELECT COUNT (*) "Email Count" , EXTRACT(year FROM date_send) "Year",EXTRACT(month FROM date_send) "Month"
In eMessaging license XML file, value of <MaxEmail></MaxEmail> represents monthly limit of emails. For example <MaxEmail>35</MaxEmail> under environment name 'e-messaging' means monthly limit is 35,000 emails.

Sometimes, there is unexpected increases in email count which could be caused by a situation where an inbound email that is 'bounced' or 'Out of office' (OOO) notification but, does not contain standard header information. Therefore, e-Messaging considers it as a fresh inbound email and hence increases the count.

'License limit exceeded exception' occurs when total count of occurrences of above messages (or 'Email Count' returned by Query) for that month, goes beyond monthly limit as per license file. This is a desired behaviour.
UPDATED:  April 12, 2017