I tested the following APIs defined in AQPivotDataSet in different combinations using SVN r39851/15.0.0-beta-29:
   var pivotTable = aqua.data.newPivotDataSet();
   pivotTable.addColumnField(fieldName);
   pivotTable.addDataField(fieldName);
   pivotTable.addRowField(fieldName);
   pivotTable.clearColumnFields();
   pivotTable.clearColumnFieldSortOrderSettings();
   pivotTable.clearDataColumnSortSettings();
   pivotTable.clearDataFieldSummaryTypeSettings();
   pivotTable.clearRowFields();
   pivotTable.clearRowFieldSortOrderSettings();
   pivotTable.setColumnFieldSortAscending(fieldName);
   pivotTable.setColumnFieldSortDescending(fieldName);
   pivotTable.setDataFieldSummaryMean(fieldName);
   pivotTable.setRowFieldSortAscending(fieldName);
   pivotTable.setRowFieldSortDescending(fieldName);
   pivotTable.sortDataColumnAscending(columnIndex);
   pivotTable.sortDataColumnDescending(columnIndex);
   pivotTable.setDataSet(dataSet);
I compared the results of Text Grid and HMTL page generated by Open API to the one generated by ADS Pivot Gird, they seem to be consistent. The only difference is: in Open API, when pivotTable.setDataFieldSummaryMean(fieldName) is used, it also affects the way how "Grand Total" cell is calculated as well, I think that is by design.

I went through AQPivotDataSet OpenAPI sample scripts and they matched in both v14 and v15. @fung: I was not able to see any difference in setDataFieldSummaryMean(fieldName). Can you attach a screenshot ?

@tariq, the 'difference' mentioned in my previous comment meant the different between the output generated by ADS Pivot Grid and the output generated by Open API (see step 8 below); not the difference between the output generated by v14-Open-API and the output generated by v15-Open-API.

Here is an example:
(1) Connection to SQL Server 2000 running on xxx.xxx.11.54 with database set to Northwind.
(2) Execute 'select top 15 * from Orders'.
(3) In ADS Pivot Grid:
       Drop ShipCountry and ShipName to 'Row Fields'.
       Drop ShipRegion and ShipCity to 'Column Fields'.
       Drop Freight to 'Data Fields'.
(4) Run attached ADS script (make sure connection is set correctly) and generate the output in browser.
(5) Compare the results of (3) and (4), they are the same, see attached SampleOutput-1 screenshot.
(6) In ADS Pivot Grid:
       Right click Freight label displayed Data Fields and select 'Field Settings...'.
       In 'Pivot Grid Field' dialog, select Average from the 'Summary (For Data Fields)' pull-down menu.
       Click OK button.
(7) Modify attached ADS script, uncomment line #85 (shown below), run script and generate the output in browser.
       pivotTable.setDataFieldSummaryMean(dataSummaryFieldName);
(8) Compare the results of (6) and (7), you will notice the followings:
       The values displayed in ADS-Pivot-Grid Grand Total cells are in Sum.
       The values displayed in Open-API Grand Total cells are in Average.
    See attached SampleOutput-2 screenshot.

We should also test the .setPivotResultSettings aqua command.  e.g. :

select * from orders
GO
.setPivotResultSettings 'Index=1,
    RowFields="[ShipCity] {None,SummaryCount,GrandCount} ASC",
    ColFields="[ShipRegion] {None,SummaryCount,GrandCount} ASC",
    DataFields="[PivotCount] {SummaryCount,GrandCount}",
    ShowChart=false,
    ShowToolbar=true,
    Paging=true,
    Split=425,
    ...

I did a quick comparison for .setPivotResultSettings for v14 and v15 and they do function the same. Attached screenshots and scripts for both v14 and v15 versions