PM customizing - How can I make editable a field after release of Maintenance order

Hi all,

I have to make editable a field after release of Maintenance order.

I go to transaction IW32 and open an existing order (order should be already released) clicking “header data”

I see some fields that can be editable: I would like to have the field “Costs” editable. Currently this field is a display only after release of the order as we can see below

I am quite sure that it is possible to make editable in the customizing.

Indeed the field “Costs” is highlighted in blue as I have changed the setting in the customizing, at the following  path:

Plant Maintenance and Customer Service --> Maintenance and service processing à Maintenance and service orders à define field selection  for order operation (PM and CS)

If you go on this path and choose the first option below

Then select “Screen groups”

And double click on 

If you scroll the list of the field  you will see the field “Estimated costs” that is the “Costs” field in the Header that I try to make it editable. It is highlighted in blu because I have flagged as you can see:

Can anyone help me how to make it editable?

Thanks in advance