Hello Rabbit,
Actually, Sydney is a centralized intake processing office, their job is to receive the application, to make sure it is complete, to make sure that the applicant fulfills the basic requirements for citizenship, once all of this is done, they do the basic data entry ( ecas...) they transfer the application the the local office where the application gets cross checked, the security profile of the applicant gets verified, then the local office can check if the applicant really lives in Canada, they have the right to investigate to make sure that the information that the applicant provided in his application is true, once all of this is done, the local office places the application in the citizenship test pipeline, they organize the test sessions, and they finalize the file so that a citizenship judge gives his final decision on whether to grant citizenship or not.
I hope this answers yours question