This agreement is made as two message matches both parties read and understand already. Therefore, it is important for seal signature of witnesses and different people each.
This is an agreement on a second edition of this text matches the two sides have read and understood it all along. The signature stamp the presence of witnesses and the person holding it.
This agreement made two copies of this text match both sides have read and understood the well throughout. The seal is a important sign in front of a witness and hold a different version.