Drill across in the KPI does not work if i add numeric seperator to the description. Why?

Drill across in the KPI does not work if i add numeric seperator to the description. Why?

As part of the Dimension definition, provide both the column and description property and assign the numeric separator for the description instead of code in the data model (dbmodel.xml). We should not assign numeric separator to the code because the same will be appended to the Query and hence the KPI execution will fail.