AnswerNOTE: This is internal information not to be given to the customer.
If MailEssentials is installed on the same machine as MS Exchange, the customer is granted a 5 user buffer for their license count. This is because it is likely that the customer has some Exchange resource mailboxes - and those are not counted.
In the license count logs, you will see that although the AD/LDAP query pulls a number of users, it will report 5 less. This is normal and you are advised to let the customer know not to worry about the user count if their filtering is not affected.