Australian applying for Chinese visa

Good evening

I am an Australian that currently has a double entry permit to China valid from April 11 2016 to October 11 2016. My first entry will be into Beijing, and my second entry will be from North Korea thus using up both my entries. I will exit from PRC to Mongolia where I will hope to apply for another single entry permit to PRC as I will be hoping to re-enter PRC from Vladivostok, Russia.

Do I need to be out of PRC for a minimum time before I can apply for a PRC entry permit at the Mongolian embassy, or can I apply two days after exiting PRC?