Aggregation in HANA

Hi,

I am creating calculation view based on SAP HANA300. Here I have created two aggregations combined in join and mapping done for source and target.
Aggregation 1 has actual and aggregation 2 are plnd values.
In union I did mapping for source and target. Here my question is when mapping aggregation 1 fields to aggregation 2, in out put, only vaules for aggregation2 are displayed. Basically I didnt understood what SAP is trying to say. After mapping why only aggregation 2 values aer shown in output?

Thanks
Sri