This can be done by creating a second calculated field similar to the following:
if [Count Of USER_ID]=2 then "2 Invoices"
elseif [Count Of USER_ID]>=3 then "3 Invoices"
User_ID will need to be on the view in order for it to work as desired.
Hope this helps!
Here is an example of what Tracy is recommending, built using the Superstore sample data. I wrote a calculation similar to what Tracy described, and used that calculation on the Rows shelf, with COUNTD(Customer ID) on the Columns shelf, and the Customer ID dimension on the Level of Detail. Unfortunately, this means that the bars are broken into individual chunks for each Customer, so I removed the border from the bars so it appears as one large chunk. There are other methods to obtaining these same results, but I haven't fully familiarized myself with those methods yet.
Order Quantities ML.twbx.zip 927.2 KB