Unless something drastic has changed that @franz hasn't told us about (and I highly doubt that), Flex daily schedules get checked an hour before they are scheduled to run.
Back in July 2015 @franz said
" The calendar itself is just a prediction, using forecasted data. One hour before the flex schedule runs we get the current forecast, look at the current soil moisture level, and decide if we need to water. If it is on the calendar, it doesn't necessarily mean that a watering will take place."
It's in this thread.
Also, the saturation level is set at 110%. Because of rounding you are seeing 108%. I often see 111%, again because of rounding.