Calculate datetime field on create transition

[April Alletha Lopez]

I am trying to use a post function to populate a datetime field on create.

DateTime1, RadioButtonValue1 => are fields on create screen

DateTime2 => Scripted field, calculated based on DateTime1 and RadioButtonValue1, available on edit screen

DateTime3 => DateTime field, editable on edit screen, should have the same value as DateTime2 after create transition.

I tried using "Copy Value From Other Field" to copy DateTime2 to DateTime3. I also tried "Script Post-Function" and "converted" the scripted field script of DateTime2. For both, I also tried to rearrange the sequence of post functions. But still not working.

Any advise?