Hi Rebecca, 

What you've described is how we currently have them set up. However, some of our customers still have trouble understanding it, so I was there was a way to set up a specific field which could be called "service period" or something like that, and the month could be linked to the month of the invoice date. 

A few of our recurring transactions are billed annually, so the service period field would be especially helpful for those which don't line up with the invoice date/ due date.