RM 9.1 feedback : Auto-Model /Calculation of the Std-dev of the performance

Hi,

There is an inconsistency between the standard deviation of the performance delivered by the Performance Average (Robust) operator :

 
and the Standard deviation of the logged performance (inside the CV) calculated via the Aggregate operator :   

We can see that the average of the performance is the same in both case.
How explain this difference of results ?

Regards,
Lionel

NB : The process in attached file