Ability to add lines to the Negotiation where outcome is CPA

I have created a Negotiation style CPA (with unchecking the line details), Negotiation template CPA. I have associated the template to the style. Now, when i am creating a Negotiation, i am still able to add lines to the Negotiation where outcome is CPA and Negotiation style CPA where line details are unchecked. Please advise.

I understand system will not stop from creating lines in Negotiation currently. But i am not sure what is the purpose of creating a Negotiation style CPA (with unchecking the line details) and the role of the same in creating a Negotiation if this is allowing me to still add Negotiation lines when the outcome is CPA.