They do not acknowledge additional documents receipt. If the additional documents u provided is sufficient, then u will receive AIP & SA soon but if it ain’t sufficient, then u will get another request saying it ain’t sufficient. As long as u submitted it on gckey and it shows that it has been uploaded and submitted then it means they have received it. What documents did they request for and when was your app received? Also, when was the additional documents received and when did u pass medicals?