Currently, if a new pivot value is added to a pivot table, the new value doesn't automatically pull in to a dashboard chart. You have to go and edit the dashboard chart to now pull in the new value.
It would be nice if you could point the dashboard chart to the pivot table as a whole, so that when that pivot table grows, the dashboard chart would adjust automatically to include the new value.
There is a workaround I've discovered, but it's manual and defeats the point of having the Pivot App.