Depending on how "Count a multiple sending as" is configured under the Options tab, the same traffic report may show different figures for sent/received messages. The fact that you configure the report to show Partners or recipients detail is also a key factor on how messages are counted for.

1 Message count:

If Partners is not selected in the Detail section of the Options tab, 1 message will be counted for each partner, regardless of the number of recipients. If for instance you sent a message to 2 recipients in the Exchange organization and 2 recipients outside the organization (different partners), only 2 messages will be counted for (1 for Exchange and 1 for Internet partner).

When selecting Partners in the Detail section of the Options tab, if the recipients (above exemple) are in the same admin group (internal users) and different SMTP domains (external users), the number of messages will be 3 (1 for the admin group and 1 for each SMTP domain). If the the internal users are in different admin groups, the number of messages will be 4.

If Recipients is selected in the Detail section of the Options tab, the number of messages will be 4 even if the internal users belong to the same admin group.

n Messages count:

When n Messages is selected under the options tab, all messages will be counted for. In other words, if we refer to the above exemple, the total of messages will be 4. In this case, the number of sent messages should be similar or close to the number of received messages.