@igor1 - This is from the support document.
Fixed Schedule Tips
If you’re using Fixed Schedules, please note they are static and do not automatically update like Flex schedules do. As such, if you make adjustments to any of the Advanced Zones Settings, remember to recreate your watering times for the inputs to be properly calculated.
Real-time Flex Schedule Manipulation
One of the great things about flex schedules, is that they are flexible. Feel free to modify zone settings and go back to the calendar view or flex schedule to dynamically see run times and/or frequency change as you modify characteristics.