My Daily Flex grass schedule typically waters for 33 minutes. I have it set to water any day except Friday. But when I look at future dates on the calendar, there is one day in the future with a different duration, such as 26 minutes.
With Daily Flex, I thought that the duration was supposed to be the same each time with only the frequency changing.
If you exclude days from the schedule, it sometimes can do short runs if it feels the ET for that omitted day will cause the moisture level to bottom out. So it give it just enough water to “hold it over” until Saturday when the normal schedule can run.