You can display the top/bottom member value as KPIs by using BellaDati formulas.
If you want to display the name of the top city according to number of units sold, here is code you could use. Here we use membersSum to loop through each city for the total units.
You can also write the formula in this way:
If you want to display the bottom city with least total units. Here it is:
Here is how the result will look like in the view: