Ramesh, Ramesh, we are talking about different things :-(
Like your driver\'s license, you show it when neccessary but you can use that for millions times. The two copies are for your convenience. For instance if you have an agent order airline ticket for you, you may have to give him/her the "airline copy" and he will return it with your ticket to you, clear, man?
Of course AP is a multi-entry document, of course! Keep it, show it, keep it.