Unfortunately the information given is just zero despite of many words and picture.
It is neither known what characteristics you have, for what reason you use the exit, what data you have in the PO to match with the strategy.
If that from the picture is all what you have in your enhancement, then you do not need the enhancement. Here you should usually have coding to calculate and check data which is not available to be used as characteristic in your classification.
If you are not an ABAPer then pass your requirement via a function specification to your ABAP team, or take the BC400 training.
Please take the time a read my blog Purchasing Release Strategy - an expanded explanation and a GPS through SCN and SAP notes
It has links to valuable documents that explain in detail how the exit is used