Setting a time interval for an automatic message

I have a form where a user needs to set how often and at what time a certain report is send from the system. The report is created and sent automatically. In the current system the form looks like this; The time interval means that the report is sent every 60 seconds. Time offset means the offset from an equal minute. With the values in the image, the report would be send at 10:00:15, 10:01,15, 10:02:15, etc. If the offset would be 0, the report would be send at 10:00:00, 10:01:00, and so on.

This design is quite difficult to understand. What would be a better to tell the user what the time interval and offset mean? Should I add examples? The use case here is that usually send interval is at an equal minute mark, but sometimes the offset is needed. Furthermore, there might be rare cases where one would want to send the report, for example at every 45 seconds.