KB15075: How to create a subtotal to sum the metric values for each rank of the N-tile metric in MicroStrategy Developer 9.4.x-10.x

SYMPTOM:
When using the subtotal feature to sum the metric values for the N-tile metric, the user cannot select to apply the subtotal to calculate across the N-tile metric level to show the total value for each of the rank in Strategy Developer 9.4.x-10.x.
 
STEPS TO REPRODUCE:
Follow the steps below to reproduce the issue in the Strategy Tutorial project:

• Create a metric as NTile(Revenue), with the Parameters set as Ascending 'True' and Tile '4'. Save and close the metric as 'Ntile Revenue' as shown below:
  

• Create a report with the attribute 'Region' and the metrics 'Revenue' and 'NTile Revenue'.
• Go to Data > Advanced Sorting, add new sorting criteria to the rows section, and select to sort by NTile Revenue metric with ascending order, as shown below:
  

• Go to Data > Subtotals > Total, and click on the advanced tab. Notice the only level available under the 'Across level' option is the attribute 'Region'. Select 'Region' and click OK.
• Save and close the report as 'Test Nile'. Execute the report and notice the report only shows the subtotal of the attribute Region, as illustrated below:
  

ACTION:
In order to apply the subtotal to calculate across theN-tile metric level, follow the steps below:

• Create a custom group with four elements as set qualification on the metric 'Ntile Revenue', each element (Tile) as `Set of Region where (NTile Revenue Exactly `Tile number`) respectively. Save and close as 'Region Ntile rank' as shown below:
  

• Edit the report 'Test Ntile' to remove the metric 'NTile Revenue' and add in the custom group 'Region Ntile rank'.
• Go to Data > Subtotals > Total, click on the advanced tab, and select across level 'Region' and 'Region Ntile rank' as shown below:
  

• Execute the report, and notice it now show the subtotals for each Region rank, and the total for all Regions, as shown below: