Reports: The "GROUPING" feature does not work properly with "Ascending or Descending"

Reports: The "GROUPING" feature does not work properly with "Ascending or Descending"

The Grouping module does now work properly when using the Ascending or Descending fields. 

I am summarizing the following three fields: 
  1. Account Type 
  2. Account Name 
  3. Probability %
The first two columns Account Type & Account Name group correctly but the Probability % with the "SORT ORDER" is not working correctly. 

Thanks.