Supply Planning not honoring manual changes in planned order

Summary:

We have a requirement where in the planned order dates would be changed, if there is a resource overload on a particular day. In such case, we are trying to manually change the firm date and quantity for a Planned order.

Initial planned order suggestion on 25th-Jan: 5000

We know that plant cannot manufacture 5000, hence we have pushed it in the future.

Planned order after changes:

25th Jan: 3000

26th Jan: 1000

27th Jan: 1000

The planned orders for 26th Jan and 27th Jan are marked as firm. Override firm quantity is set as none. After the plan is run again, the firm planned orders are preserved. But the original planned order is still having the quantity again as 5000. It is expected that it should remain as 3000, as the additional quantity is already adjusted in coming days.