Block cancelling the cleared billing documents

Hi Friends,

Currently system is allowing to cancel the cleared billing document and business does want to do that, for example when F2 billing type document is cancelled then it is generating S1 type cancelled document.

I think I can prevent this by config ( in VOFA for billing type F2 under section cancellation >Copying requirements > assign 29.

And I need to do it for all billing types,

Now my queries are:

Do I need to do any config for cancelled billing type (S1) as well ?

Is there complication for doing that?

Whether I would be able to cancel the uncleared billing document in this way?

Or just I can proceed what I mentioned above.

Regards

Ashu