I have just a bit of clarification. On the subject of changing the statement of ordinary residence, it can be changed any time during the year, but it is not effective until 60 days after it's been received by the commanding officer.
During an election period, as General Corbould mentioned, after the writ is dropped, if you move to change your statement of ordinary residence, it is not effective until 14 days after the election period. So during an election period you cannot change a statement of ordinary residence, but during the course of the year, your statement of ordinary residence can be changed to the place where you would live but for your military service, or the location where you are currently serving, or the location that you held immediately prior to enrolment.
So there is some flexibility in aligning your statement of ordinary residence with your connection to the community.