Address Change

There is a post saying "
If my son is studying in another city but his peamanent address is still our address, does he need file a notice of change of address? Thank you." Mytwocents replied "not necessarily".

I have a following question. Is it ture: as long as your permanent address stays the same (say, you work in another city, but your family stay in the old address), there is no need to file AR-11?

Thanks.