Hello kefpa01,
In addition to my previos comment, you can get the screen value for 8daysAway by clicking on Advanced on DueDateEnd
anc click on SQL Override.
The important thing on SqlOverride is Step 3 as we are more focused on getting the screen value for 8DaysAway field.
In step 1, you can choose Activity table and in Step 2: choose any field.
In step 3: Select DueDateEnd < Value from Screen select 8DaysAway.
Then, go to step 4 and click on Generate SQL and it will generate the code and you can get the value of 8daysaway from the code.(See Screenshot).
You can now use this value in your override.