Change invoice date range

We manage a handful of client accounts for whom we do call tracking, and we bill our clients at the start of each month for the services rendered in the previous month. It would be incredibly helpful if CallRail had the option to set the invoice period for the entirety of a month (ie; July 1st-July 31st) instead of starting on the day that the account was originally created (ie: July 8th-August 8th), so that the invoices line up with common end-of-month billing periods.