MA on save verification script vs MA field validation script

Hi Experts,

I have created one extension field in maser agreement extensions section , to display some text.

The text should display in the new extension field when I duplicate an existing master agreement and saved it.

For this I wrote script and added to existing "MA on save verification script".

The script executes and displays the text in the new extension field on save. But if I reopen the same MA the new extension field is showing empty.

I have added the same code snippet to existing MA field validation script.

It is not displaying the text in the new extension field immediately after duplication and save.

It shows the text only  when I open that MA ,  do some field change and save it.

But I would like to display it immediately on save event.

Can you please guide.

Thanks

Raj