Our patients run on different intervals for cleaning. Some are every 3 months, some are every 4 months, and some are every 6 months. When I went back to set the interval for previous patients, I realized that the interval only works from the day I am setting it, rather than the previous time a patient got a cleaning. It would be much more helpful to be able to set the interval from the previous date of service. That way, our system would send out automatic reminders for patients to come back for the intervals of individual patients.