Hi Mayur,
Can you go through the Datasources i suggested Coz it will capture all the values of the PO,irrestive of the number of times it changed,the data is stored in Change Log (for normal Keys of the DSO).Try checking such scenarios on DSO based on 2LIS_02_ITM.
The trick lies in Defining the Key figures of the DSO ,say on top of 2LIS_02_ITM and further data Modelling.
If it still does not satisfy the criteria then go for FM based Datasource.
rgds
SVU123