The Report Writer email messages report doesn't give an accurate report on when recurring messages were sent. It appears that recurring deliveries, like a Welcome Series, are counted towards the totals of the month in which they are started. It doesn't give you an accurate reading on the recurring delivery messages that are sent each month. It instead counts them from the initial send. When a user intends to know how many emails were sent, it should be from the send date, not the origin date.