Hello Heidi Barnes,
Welcome to the Community forums. Questions related to Totals and Grand totals are one of the more frequent questions we hear.
One of the features added to version 8.1 is to define the aggregation of choice for Totals. By default, a Total of a Countd() field will be the Total Unique Count of the dimension in question. This is by design and expected. However, you can change this behavior to a Sum() of the Countd() of a dimension that has been partitioned by another Dimension.
In the example attached on the tab "Total Using Sum", I have modified the Measure on the Labels shelf to utilize "Sum" rather than "Automatic". To arrive at this same value in Tableau 8 or earlier, we would need to utilize a Table Calculation with the calculation Window_Sum(countd([Customers])) as a separate field rather than as a total.
There are several posts in the forums related to totals and grand totals as well including this excellent post by Jonathan Drummey with links to his blog site explaining Sub Totals and Grand Totals in great detail.
I hope this helps,
Total using Sum vs Auto.twbx 367.8 KB