Why we do self-loop / realignment of DSO

Hi to all,

I have a doubt in BI.

I have seen that some time in BI Molding that we do self-loop / realignment of DSO to correct the data in DSO.

Example: we are loading the Data from PSA to DSO1 and again we are doing self-loop/ realignment to DSO1 with some logic in routine before sending to CUBE.

Please can anyone explain with some real time scenario and why we do it and how we achieve it.

Or is there any document for that.

I shall be thankful to you for this.

Regards

Pavneet Rana