2lis_11_VAITM Delta record processing

Friends,

I am using 2LIS_11_VAITM to fill an ODS which further populates a cube.

I am struggling with what date to use when I update the cube. If I use the created on date, then if there is a change to the line in the future, it posts back on the original creation date. This means history gets restated. If I use the statistics update date (generally the date of the change), it moves the entire order quantity to this date, not just the changed amount.

Consider the example:

2/1 order is created for 10 pcs, Cube shows 10 pcs on 2/1.

2/5 change order quantity to 15 pieces.

Using the created on date, 2/1 now shows 15pcs.

Using the statistics date 2/1 now shows 0 and 2/5 shows 15pcs.

What we want is 10 on 2/1 and 5 on 2/5 for a total of 15.

My ODS has keys of document number and item number, do I need something else like STORNO in the key?

Any help is appreciated.