The existing difference score is helpful, but it is frustrating that we are unable to add different metrics to the data table to run the difference score on metrics of our choosing. In the screen shot below we wanted to add the metrics in rows 4, 5, and 6. I understand rows 4 and 5 not getting a score, but row 6 should have produced a difference score.
The official help section calls out that metrics added after the difference score has run will get no results. What if we want to compare metrics that were not generated by the default table?