I may have already answered this question through support tickets. But in case I didn’t, here is the clarification about sequential/non-sequential. A station set to non-sequential will can be scheduled at any time and will start immediately without waiting for other zones. If a non-sequential station appears in a program, it will start immediately at the start time of the program. Therefore, if you have two non-sequential stations, they will both start at the same time, and they will start together with the first sequential zone.
That means if you have V1, V2 set up as non-sequential, and let’s say V3-V9 are sequential, then at the start time of the program, V1, V2, V3 will all start together. The typical use of this is to set V1 and V2’s run time to be the entire duration of the program, therefore V1 and V2 will remain open until the end of the program.
In some cases you may want V1 and V2 to start earlier than the first non-sequential station. To do that you will have to create a separate program for V1 and V2 specifically, that way you can set the V1 and V2 start time arbitrarily, such as a few minutes before your sequential stations.