The first, is using your expression variable. The action is triggered when the reload ends. Then, takes the value of vVar and put it in vV variable. In next reload, it will get this value (in table 1).
You must to know that the script area will never recognize the set analisis, only static variables.
Other way is shown in script. Obviously, with my example is easier than your variable, but if you must do the calculation in reload time, it's the only way to do it, doing the relationships and aggregations (group by, where, if, etc....)