Help on cumulative calculation in record looping

[#1]

Dear pals,

I need your help to give me some idea on how to solve the below issue.

Current data that I have

As you can see the above, my raw data will look like

What I am trying to achieve is to determine the status of each Schedule Delivery Date, because the total quantity is spread out to several schedule date with schedule quantity.

The total delivery itself also refered to the item no, thus the logic is to sort the schedule delivery date, get the Total Quantity of the item - Schedule Delivery Quantity per Schedule Date (cumulative calculation).

Please help on how I can achieve this.

Thank you.